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Transcript of Answers (Anticipation Guide and Lesson 8-1) © Glencoe/McGraw-Hill, a division of The McGraw-Hill...

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A1 Glencoe Algebra 1

Chapter Resources

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

3

Gle

ncoe A

lgeb

ra 1

An

tici

pati

on

Gu

ide

Facto

rin

g

B

efo

re y

ou

beg

in C

ha

pte

r 8

R

ead

each

sta

tem

en

t.

D

eci

de w

heth

er

you

Agre

e (

A)

or

Dis

agre

e (

D)

wit

h t

he s

tate

men

t.

W

rite

A o

r D

in

th

e f

irst

colu

mn

OR

if

you

are

not

sure

wh

eth

er

you

agre

e o

r d

isagre

e,

wri

te N

S (

Not

Su

re).

Aft

er y

ou

com

ple

te C

ha

pte

r 8

R

ere

ad

each

sta

tem

en

t an

d c

om

ple

te t

he l

ast

colu

mn

by e

nte

rin

g a

n A

or

a D

.

D

id a

ny o

f you

r op

inio

ns

abou

t th

e s

tate

men

ts c

han

ge f

rom

th

e f

irst

colu

mn

?

F

or

those

sta

tem

en

ts t

hat

you

mark

wit

h a

D,

use

a p

iece

of

pap

er

to w

rite

an

exam

ple

of

wh

y y

ou

dis

agre

e.

8 Ste

p 1

Ste

p 2

ST

EP

1A

, D

, o

r N

SS

tate

men

tS

TE

P 2

A o

r D

1.

A m

on

om

ial

is i

n f

act

ore

d f

orm

wh

en

it

is e

xp

ress

ed

as

the

pro

du

ct o

f p

rim

e n

um

bers

an

d v

ari

able

s, a

nd

no v

ari

able

has

an

exp

on

en

t gre

ate

r th

an

1.

A

2.

Th

e g

reate

st c

om

mon

fact

or

(GC

F)

of

two o

r m

ore

mon

om

ials

is

th

e p

rod

uct

of

their

un

iqu

e f

act

ors

wh

en

each

mon

om

ial

is

wri

tten

in

fact

ore

d f

orm

.A

3.

An

y t

wo n

um

bers

th

at

have a

gre

ate

st c

om

mon

fact

or

of

1 a

re

said

to b

e r

ela

tively

pri

me.

A

4.

If t

he p

rod

uct

of

an

y t

wo f

act

ors

is

0,

then

at

least

on

e o

f th

e

fact

ors

mu

st e

qu

al

0.

A

5.

A q

uad

rati

c tr

inom

ial

has

a d

egre

e o

f 4.

D

6.

To s

olv

e a

n e

qu

ati

on

su

ch a

s x

2 =

8 +

2x,

tak

e t

he s

qu

are

root

of

both

sid

es.

D

7.

Th

e p

oly

nom

ial

3r2

- r

- 2

can

not

be f

act

ore

d b

eca

use

th

e

coeff

icie

nt

of

r2 i

s n

ot

1.

D

8.

Th

e p

oly

nom

ial

t2 +

16 i

s n

ot

fact

ora

ble

. A

9.

Th

e n

um

bers

16,

64,

an

d 1

21 a

re p

erf

ect

squ

are

s.A

Answers (Anticipation Guide and Lesson 8-1)

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-1

Ch

ap

ter

8

5

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

Mo

no

mia

ls a

nd

Facto

rin

g

8-1

Fact

or

Mo

no

mia

ls A

mon

om

ial

is i

n f

act

ore

d f

orm

wh

en

it

is e

xp

ress

ed

as

the p

rod

uct

of

pri

me n

um

bers

an

d v

ari

able

s, a

nd

no v

ari

able

has

an

exp

on

en

t gre

ate

r th

an

1.

F

acto

r e

ach

mo

no

mia

l co

mp

lete

ly.

a.

42a

3

42a

3 =

2

21

a

a

a

42 =

21

2,

and a

3 =

a

a

a

= 2

3

7

a

a

a

21 =

3

7

Th

us,

42a

3 i

n f

act

ore

d f

orm

is

2

3

7

a

a

a.

b. -

40

x2y

3

-40x

2y

3 =

-1

40 x

2 y

3

Expre

ss -

40 a

s -

1

40

.

= -

1

2

20

x

x

y

y

y

40 =

20

2,

x2 =

x

x,

and y

3 =

y

y

y

= -

1

2

2

10

x

x

y

y

y

20 =

10

2

=

-1

2

2

2

5

x

x

y

y

y

10 =

5

2

Th

us,

-40

x2y

3 i

n f

act

ore

d f

orm

is

-1

2

2

2

5

x

x

y

y

y.

Exerc

ises

Fa

cto

r e

ach

mo

no

mia

l co

mp

lete

ly.

1. 32x

2

2. 18m

2n

3. 49

a3b

2

2

2

2

2

2

x

x

2

3

3

m

m

n

7

7

a

a

a

b

b

4. 18y

3

5. -

9h

3jk

2

6. -

8d

2

2

3

3

y

y

y

-

1

3

3

h

h

h

j

k

k

-

1

2

2

2

d

d

7. 66q

3r3

8. 140x

2y

4z

9. –

ab

2f

2

2 3

1

1 q

q

q

r r r

2 2

5

7

x

x

y

y

y

y

z

-

1 a

b

b

f f

10. -

17t

11. 625jk

2

12. 47w

x3yz2

-

1 1

7 t

5 5

5

5

j k

k

47 w

x

x

x

y

z

z

13. 12r4

14. -

38a

2b

15. 4

mp

2

2

3

r

r

r

r

-

1

2

19

a

a

b

2

2

m

p

Exam

ple

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A2 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

6

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

(con

tin

ued

)

Mo

no

mia

ls a

nd

Facto

rin

g

Greatest C

om

mo

n F

acto

r

Th

e p

rod

uct

of

the c

om

mon

pri

me f

act

ors

is

call

ed

th

e

gre

ate

st c

om

mon

fact

or

(GC

F)

of

the n

um

bers

. T

he g

reate

st c

om

mon

fact

or

is t

he g

reate

st

nu

mber

that

is a

fact

or

of

both

ori

gin

al

nu

mbers

.

If t

wo o

r m

ore

in

tegers

or

mon

om

ials

have n

o c

om

mon

pri

me f

act

ors

, th

eir

GC

F i

s 1 a

nd

th

e

inte

gers

or

mon

om

ials

are

said

to b

e r

ela

tiv

ely

prim

e.

F

ind

th

e G

CF

of

16xy

2z

2 a

nd

72xyz

3.

16

xy

2z2

= 2 !

2 !

2 !

2 !

x !

y !

y !

z !

z

72xyz3

= 2 !

2 !

2 !

3 !

3 !

x !

y !

z !

z !

z

Th

e G

CF

of

16

xy

2z2

an

d 7

2xyz3

is

2 !

2 !

2 !

x !

y !

z !

z o

r 8

xyz2

.

Exerc

ises

Fin

d t

he G

CF

of

ea

ch

set

of

mo

no

mia

ls.

1. 49x,

343

x2

2. 4

a7b

, 28a

b49

x

4ab

3. 96y,

12

x,

8y

4. 12a

, 18a

bc

4

6a

5. 28y

2,

35xy,

49x

2yz

6. 2m

2p

, 12

mp

2,

18m

p7

y

2m

p

7. 12x

2,

32x

2yz,

60xy

2

8. 18a

3b

2,

36a

3b

2

4x

18

a3b

2

9. 15m

n2,

30

m3n

2,

90m

3

10. 2x

2y,

9x

2y

3,

18xy

2

15

m

xy

11. a

4b,

8a

3b

2

12. a

b2,

5a

4b

2,

10

b3

a3b

b

2

13. 2

x2y

2,

8xy

4,

12x

2y

14. 6

a2b

5,

15

a3b

4

2xy

3a

2b

4

15. 21a

4b

7f2

, 84a

3b

4,

28a

5b

2f3

16. 13x

2y

5,

5xy

3,

x4y

7

a3b

2

xy

8-1 Exam

ple

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-1

Ch

ap

ter

8

7

Gle

ncoe A

lgeb

ra 1

Sk

ills

Pra

ctic

e

Mo

no

mia

ls a

nd

Facto

rin

g

Fa

cto

r e

ach

mo

no

mia

l co

mp

lete

ly.

1. 10a

4 2 �

5 �

a �

a �

a �

a

2.

-27x

3y

2

-1 �

3 �

3 �

3 ·

x �

x �

x �

y �

y

3. 28p

r2 2 �

2 �

7 �

p �

r �

r

4. 44m

2n

p3 2

� 2

� 1

1 �

m �

m �

n �

p �

p �

p

5. 9

x3y

2 3 �

3 �

x �

x �

x �

y �

y

6.

-17

ab

2f

-1 �

17 �

a �

b �

b �

f

7. 42g

2 2 �

3 �

7 �

g �

g

8. 36

tu2 2 �

2 �

3 �

3 �

t �

u �

u

9.

-4a

-

1 �

2 �

2 �

a

10.

-10x

4yz2

-

1 �

2 �

5 �

x �

x �

x �

x �

y �

z �

z

Fin

d t

he G

CF

of

ea

ch

set

of

mo

no

mia

ls.

11. 16f,

21a

b2 1

12. 18t,

48t4

6

t

13. 32xyz,

48xy

4 16

xy

14. 12m

3p

2,

44m

p3 4m

p2

15. 4

q2r2

t2,

9q

3r3

t3 q

2r2

t2

16. 14

ab

5,

7a

2b

3c

7ab

3

17. 51xyz2

, 68x

2yz2

17xyz

2

18. 12

t7u

3,

18t3

u7 6t3

u3

19. 11

a4b

3,

44a

2b

5 11

a2b

3

20. 18r3

t, 2

6qr2

t4 2

r2t

8-1

Answers (Lesson 8-1)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A3 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

8

Gle

ncoe A

lgeb

ra 1

Practi

ce

Mo

no

mia

ls a

nd

Facto

rin

g

Fa

cto

r e

ach

mo

no

mia

l co

mp

lete

ly.

1. 30d

5

2. -

72m

p

2

� 3

� 5

� d

� d

� d

� d

� d

-

1 �

2 �

2 �

2 �

3 �

3 �

m �

p

3. 81b

2c3

4. 145

abc3

3

� 3

� 3

� 3

� b

� b

� c

� c

� c

5

� 2

9 �

a �

b �

c �

c �

c

5. 168n

q2r

6. -

121

x2yz2

2

� 2

� 2

� 3

� 7

� n

� q

� q

� r

-

1 �

11 �

11 �

x �

x �

y �

z �

z

7. -

14f

2g

2

8. -

77

w4

-

1 �

2 �

7 �

f �

f �

g �

g

-1 �

7 �

11 �

w �

w �

w �

w

Fin

d t

he G

CF

of

ea

ch

set

of

mo

no

mia

ls.

9. 24fg

5,

56

f 3g 8

fg

10. 72r2

t2,

36

rt3 36

rt2

11. 15a

2b

, 35

ab

2 5

ab

12. 28k

3n

2,

45p

r2 1

13. 40xy

2,

56x

3y

2,

124x

2y

3 4

xy

2

14. 88a

3d

, 40a

2d

2,

32

a2d

8a

2d

15. G

EO

METR

Y T

he a

rea o

f a r

ect

an

gle

is

84 s

qu

are

in

ches.

Its

len

gth

an

d w

idth

are

both

wh

ole

nu

mbers

.

a.

Wh

at

is t

he m

inim

um

peri

mete

r of

the r

ect

an

gle

? 38 i

n.

b.

Wh

at

is t

he m

axim

um

peri

mete

r of

the r

ect

an

gle

? 170 i

n.

16. R

EN

OV

ATIO

N M

s. B

axte

r w

an

ts t

o t

ile a

wall

to s

erv

e a

s a s

pla

shgu

ard

above a

basi

n

in t

he b

ase

men

t. S

he p

lan

s to

use

equ

al-

sized

til

es

to c

over

an

are

a t

hat

measu

res

48 i

nch

es

by 3

6 i

nch

es.

a.

Wh

at

is t

he m

axim

um

-siz

e s

qu

are

til

e M

s. B

axte

r ca

n u

se a

nd

not

have t

o c

ut

an

y o

f

the t

iles?

12-i

n.

sq

uare

b.

How

man

y t

iles

of

this

siz

e w

ill

she n

eed

? 12

8-1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-1

Ch

ap

ter

8

9

Gle

ncoe A

lgeb

ra 1

Wo

rd

Pro

ble

m P

racti

ce

Mo

no

mia

ls a

nd

Facto

rin

g

1. M

ATH

GA

MES

M

rs.

Jen

son

’s c

lass

is

pla

yin

g “

Gu

ess

th

e M

on

om

ial.

” O

ne

stu

den

t d

isp

lays

fact

ors

of

the s

ecr

et

mon

om

ial,

an

d t

he t

eam

tri

es

to g

uess

the m

on

om

ial.

Wh

en

it

is J

am

es’

tu

rn,

he

sees

that

the s

ecr

et

mon

om

ial

is 2

10x

2y

2.

Wh

ich

of

the f

oll

ow

ing c

ard

s sh

ou

ld h

e

dis

pla

y s

o h

is t

eam

gu

ess

es

the c

orr

ect

mon

om

ial?

3x

5x

7y

11y

13z

17z

19z

O

rder

may v

ary

:

2

� 3

� 5

� 7

�x �

x�

y�

y

2. PA

RTY

FA

VO

RS

B

all

oon

s co

me i

n

pack

ages

of

18 a

nd

part

y h

ats

com

e i

n

pack

ages

of

8.

Jeff

wan

ts t

o h

ave t

he

sam

e n

um

ber

of

ball

oon

s an

d h

ats

. W

hat

is t

he f

ew

est

pack

ages

of

ball

oon

s an

d

hats

th

at

he n

eed

s to

bu

y s

o h

e h

as

no

hats

or

ball

oon

s le

ft o

ver?

4 p

ackag

es

of

ballo

on

s a

nd

9 p

ackag

es o

f h

ats

3. PA

CK

AG

ING

C

olo

r W

heel

pri

nte

r in

k

com

pan

y w

an

ts t

o d

esi

gn

a n

ew

cart

on

in

wh

ich

to p

ack

pri

nte

r in

k c

art

rid

ges

for

ship

men

t to

sto

res.

Cart

rid

ge b

oxes

are

7 i

nch

es

lon

g a

nd

3 i

nch

es

wid

e.

Wh

at

are

th

e d

imen

sion

s of

the s

mall

est

squ

are

-bott

om

cart

on

th

at

wil

l h

old

th

e

cart

rid

ge b

oxes

wit

hou

t extr

a s

pace

?

21 i

n.

by 2

1 i

n.

4. M

ATH

EM

ATIC

IAN

S A

Gre

ek

math

em

ati

cian

an

d a

stro

nom

er

nam

ed

Era

tost

hen

es

create

d a

way t

o s

ep

ara

te

pri

me n

um

bers

fro

m c

om

posi

te n

um

bers

.

His

meth

od

is

kn

ow

n a

s th

e S

ieve o

f

Era

tost

hen

es.

It

pro

ceed

s as

foll

ow

s.

So

urc

e:

Math

Foru

m

Recr

eate

th

e S

ieve o

f E

rato

sth

en

es

to

fin

d t

he f

irst

11 p

rim

e n

um

bers

. 2,

3,

5,

7,

11,

13,

17,

19,

23,

29,

31

5. R

EPA

IRS

Heid

i w

an

ts t

o r

ep

lace

th

e

floor

in h

er

16-f

oot

by 1

8-f

oot

rect

an

gu

lar

dan

ce s

tud

io.

Sh

e w

an

ts t

o u

se s

qu

are

wood

til

es,

an

d s

he d

oes

not

wan

t to

have

to c

ut

an

y o

f th

e t

iles

nor

leave a

ny g

ap

s.

a.

Su

pp

ose

th

e f

loori

ng c

om

pan

y c

an

use

an

y s

ize t

ile.

Wh

at

is t

he l

arg

est

squ

are

til

e t

hat

Heid

i ca

n u

se f

or

the

new

flo

or?

2 f

eet

by 2

feet

b.

If H

eid

i fi

rst

kn

ock

s ou

t a w

all

an

d

incr

ease

s th

e s

tud

io t

o 2

4 f

eet

by

18 f

eet,

wh

at

is t

he l

arg

est

squ

are

til

e

she c

an

use

for

the n

ew

flo

or?

6 f

oo

t b

y 6

fo

ot

8-1

Write

num

bers

1 t

o 5

0.

Sin

ce 1

is n

either

prim

e n

or

com

posite,

ignore

1.

Circle

the n

um

ber

2,

and t

hen c

ross o

ff e

very

num

ber

that

is d

ivis

ible

by 2

.

Circle

the n

ext

num

ber

that

is n

ot

cro

ssed o

ff,

3,

and c

ross o

ff a

ll m

ultip

les o

f 3.

Circle

the n

ext

num

ber

that

is n

ot

cro

ssed o

ff,

5,

and c

ross o

ff t

he

multip

les o

f 5,

etc

Answers (Lesson 8-1)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A4 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

10

Gle

ncoe A

lgeb

ra 1

En

rich

men

t

Fin

din

g t

he G

CF b

y E

uclid

’s A

lgo

rith

mF

ind

ing t

he g

reate

st c

om

mon

fact

or

of

two l

arg

e n

um

bers

can

tak

e a

lo

ng t

ime u

sin

g p

rim

e f

act

ori

zati

on

s. T

his

meth

od

can

be a

void

ed

by

usi

ng E

ucl

id’s

Alg

ori

thm

as

show

n i

n t

he f

oll

ow

ing e

xam

ple

.

F

ind

th

e G

CF

of

209 a

nd

532.

Div

ide t

he g

reate

r n

um

ber,

532,

by t

he l

ess

er,

209.

Th

e d

ivis

or,

19,

is t

he G

CF

of

209 a

nd

532.

Su

pp

ose

th

e G

CF

of

two n

um

bers

is

fou

nd

to b

e 1

. T

hen

th

e n

um

bers

are

said

to b

e r

ela

tiv

ely

prim

e.

Fin

d t

he G

CF

of

ea

ch

gro

up

of

nu

mb

ers b

y u

sin

g E

ucli

d’s

Alg

orit

hm

.

1. 187;

578 17

2. 1802;

106 106

3. 161;

943 23

4. 215;

1849 43

5. 1325;

3498 53

6. 3484;

5963 67

7. 33,5

83;

4257 473

8. 453;

484 1 (

rela

tively

pri

me)

9. 95;

209;

589 19

10. 518;

407;

851 37

11. 17a

2x

2z;

1615

axz2

17axz

12. 752

af 3

; 893

a3f 3

47af 3

13. 979

r2t2

; 495

rt3,

154

r3t3

11rt

2

14. 360

x5y

7;

328

xy;

568

x3y

3 8

xy

8-1 Exam

ple

Div

ide t

he r

em

ain

der

into

th

e d

ivis

or

above.

Rep

eat

this

pro

cess

u

nti

l th

e r

em

ain

der

is z

ero

. T

he l

ast

n

on

zero

rem

ain

der

is

the G

CF

.

2

209 � ����

����������

���� 532

__

__

418 1

114 � �

����������

�������

209

__

__

114 1

95 � �

����������

�������

114

__

_ 95 5

19 � �

����������

�� 95

__

_ 95

0

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-2

Ch

ap

ter

8

11

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

Usin

g t

he D

istr

ibu

tive P

rop

ert

y

Use

th

e D

istr

ibu

tive P

rop

ert

y t

o F

act

or

Th

e D

istr

ibu

tive P

rop

ert

y h

as

been

use

d

to m

ult

iply

a p

oly

nom

ial

by a

mon

om

ial.

It

can

als

o b

e u

sed

to e

xp

ress

a p

oly

nom

ial

in

fact

ore

d f

orm

. C

om

pare

th

e t

wo c

olu

mn

s in

th

e t

able

belo

w.

U

se t

he D

istr

ibu

tiv

e

Pro

perty

to

fa

cto

r 1

2mp

+ 8

0m

2.

Fin

d t

he G

CF

of

12m

p a

nd

80m

2.

12m

p =

2 �

2 �

3 �

m �

p

80

m2 =

2 �

2 �

2 �

2 �

5 �

m �

m

GC

F =

2 �

2 �

m o

r 4m

Wri

te e

ach

term

as

the p

rod

uct

of

the G

CF

an

d i

ts r

em

ain

ing f

act

ors

.

12

mp

+ 8

0m

2 =

4m

(3 �

p)

+ 4

m(2

� 2

� 5

� m

)

= 4

m(3

p)

+ 4

m(2

0m

)

= 4

m(3

p +

20m

)

Th

us

12

mp

+ 8

0m

2 =

4m

(3p

+ 2

0m

).

F

acto

r

6ax +

3ay +

2bx

+ by b

y g

ro

up

ing

.

6a

x +

3a

y +

2bx +

by

= (

6a

x +

3a

y)

+ (

2bx +

by)

= 3

a(2

x +

y)

+ b

(2x +

y)

= (

3a

+ b

)(2x +

y)

Ch

eck

usi

ng t

he F

OIL

meth

od

.

(3a

+ b

)(2

x +

y)

= 3

a(2

x)

+ (

3a

)(y)

+ (

b)(

2x)

+ (

b)(

y)

= 6

ax +

3a

y +

2bx +

by ✓

Exerc

ises

Fa

cto

r e

ach

po

lyn

om

ial.

1. 24x +

48y

2. 30

mp

2 +

m2p

- 6

p

3. q

4 -

18q

3 +

22

q

2

4(x

+ 2

y)

p(3

0m

p +

m2 -

6)

q(q

3 -

18q

2 +

22)

4. 9

x2 -

3x

5. 4

m +

6p

- 8

mp

6. 45

r3 -

15r2

3

x(3

x -

1)

2(2

m +

3p

- 4

mp

) 1

5r2

(3r -

1)

7. 14t3

- 4

2t5

- 4

9t4

8. 55p

2 -

11p

4 +

44

p5

9. 14y

3 -

28

y2 +

y

7

t3(2

- 6

t2 -

7t)

1

1p

2(5

- p

2 +

4p

3)

y(1

4y

2 -

28y +

1)

10. 4

x +

12x

2 +

16x

3

11. 4a

2b

+ 2

8a

b2 +

7a

b

12. 6y +

12x -

8z

4

x(1

+ 3

x +

4x

2)

ab

(4a +

28b

+ 7

) 2

(3y +

6x -

4z)

13. x

2 +

2x +

x +

2

14. 6

y2 -

4y +

3y -

2

15. 4

m2 +

4m

p +

3m

p +

3p

2

(

x +

1)(

x +

2)

(2

y +

1)(

3y -

2)

(4

m +

3p

)(m

+ p

)

16. 12a

x +

3xz

+ 4

ay +

yz

17. 12

a2 +

3a

- 8

a -

2

18. xa

+ y

a +

x +

y

(

3x +

y)(

4a

+ z

) (

4a +

1)(

3a

- 2

) (

x +

y)(

a +

1)

8-2

Exam

ple

1Exam

ple

2

Mu

ltip

lyin

gF

acto

rin

g

3(a

+ b

) =

3a

+ 3

b3

a +

3b

= 3

(a +

b)

x(y

- z

) =

xy -

xz

xy -

xz =

x(y

- z

)

6y(2

x +

1)

= 6

y(2

x)

+ 6

y(1

)

=

12

xy +

6y

12

xy +

6y =

6y(2

x)

+ 6

y(1

)

=

6y(2

x +

1)

Answers (Lesson 8-1 and Lesson 8-2)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A5 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

12

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

(con

tin

ued

)

Usin

g t

he D

istr

ibu

tive P

rop

ert

y

So

lve E

qu

ati

on

s b

y F

act

ori

ng

T

he f

oll

ow

ing p

rop

ert

y,

alo

ng w

ith

fact

ori

ng,

can

be

use

d t

o s

olv

e c

ert

ain

equ

ati

on

s.

S

olv

e 9x

2 +

x =

0.

Th

en

ch

eck

th

e s

olu

tio

ns.

Wri

te t

he e

qu

ati

on

so t

hat

it i

s of

the f

orm

ab

= 0

.

9x

2 +

x =

0

Origin

al equation

x(9

x +

1) =

0

Facto

r th

e G

CF

of

9x

2 +

x,

whic

h is x

.

x =

0 or

9x +

1 =

0

Zero

Pro

duct

Pro

pert

y

x =

0 x

= -

1 −

9

Solv

e e

ach e

quation.

Th

e s

olu

tion

set

is {0

, -

1 −

9 } .

Ch

eck

S

ubst

itu

te 0

an

d -

1 −

9 f

or

x i

n t

he o

rigin

al

equ

ati

on

.

9x

2 +

x =

0

9x

2 +

x =

0

9(0

)2 +

0 "

0

9 (- 1

9 ) 2

+ (-

1 −

9 ) "

0

0 =

0 ✓

1

9 +

(- 1

9 ) "

0

0 =

0 ✓

So

lve e

ach

eq

ua

tio

n.

Ch

eck

yo

ur s

olu

tio

ns.

1. x(x

+ 3

) =

0

2. 3m

(m -

4) =

0

3. (r

- 3

)(r +

2) =

0

{

0, -

3}

{0,

4}

{-

2,

3}

4. 3

x(2

x -

1) =

0

5. (4

m +

8)(

m -

3) =

0

6. 5t2

= 2

5t

{

0,

1

2 }

{-

2,

3}

{0,

5}

7. (4

c +

2)(

2c -

7) =

0

8. 5p

- 1

5p

2 =

0

9. 4y

2 =

28y

{- 1

2 ,

7

2 }

{0,

1

3 }

{0,

7}

10. 12x

2 =

-6

x

11. (4

a +

3)(

8a

+ 7

) =

0

12. 8y =

12y

2

{- 1

2 ,

0}

{- 7

8 , - 3

4 }

{0,

2

3 }

13. x

2 =

-2

x

14. (6

y -

4)(

y +

3) =

0

15. 4m

2 =

4m

{-

2,

0}

{-

3,

2

3 }

{0,

1}

16. 12x =

3x

2

17. 12a

2 =

-3

a

18. (1

2a

+ 4

)(3a

- 1

) =

0

{

0,

4}

{- 1

4 ,

0}

{- 1

3 ,

1

3 }

8-2 Exam

ple

Exerc

ises

Zero

Pro

du

ct

Pro

pert

yF

or

any r

eal num

bers

a a

nd b

, if

ab

= 0

, th

en e

ither

a =

0,

b =

0,

or

both

a a

nd b

equal 0.

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-2

Ch

ap

ter

8

13

Gle

ncoe A

lgeb

ra 1

Sk

ills

Pra

ctic

e

Usin

g t

he D

istr

ibu

tive P

rop

ert

y

Fa

cto

r e

ach

po

lyn

om

ial.

1. 7

x +

49

2. 8

m -

6

7

(x +

7)

2(4

m -

3)

3. 5

a2 -

15

4. 10

q -

25q

2

5

(a2 -

3)

5q

(2 -

5q

)

5. 8

ax -

56a

6. 81r +

48

rt

8

a(x

- 7

) 3

r(2

7 +

16

t)

7. t2

h +

3t

8. a

2b

2 +

a

t

(th

+ 3

) a

(ab

2 +

1)

9. x +

x2y +

x3y

2

10. 3

p2r2

+ 6

pr +

p

x

(1 +

xy +

x2y

2)

p(3

pr2

+ 6

r +

1)

11. 4a

2b

2 +

16a

b +

12a

12. 10

h3n

3 -

2h

n2 +

14h

n

4

a(a

b2 +

4b

+ 3

) 2

hn

(5h

2n

2 -

n +

7)

13. x

2 +

3x +

x +

3

14. b

2 -

2b

+ 3

b -

6

(

x +

1)(

x +

3)

(b

+ 3

)(b

- 2

)

15. 2

j 2 +

2j +

3j +

3

16. 2a

2 -

4a

+ a

- 2

(

2j +

3)(

j +

1)

(2a

+ 1

)(a -

2)

17. 6

t2 -

4t -

3t +

2

18. 9x

2 -

3xy +

6x -

2y

(

2t -

1)(

3t -

2)

(3x +

2)(

3x -

y)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

yo

ur s

olu

tio

ns.

19. x(x

- 8

) =

0 {0

, 8}

20. b(b

+ 1

2) =

0 {-

12,

0}

21. (m

- 3

)(m

+ 5

) =

0 {-

5,

3}

22. (a

- 9

)(2

a +

1) =

0 {- 1

2 ,

9}

23. x

2 -

5x =

0 {0

, 5}

24. y

2 +

3y =

0 {-

3,

0}

25. 3a

2 =

6a

{0

, 2}

26. 2

x2 =

3x {0

, 3

2 }

8-2

Answers (Lesson 8-2)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A6 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

14

Gle

ncoe A

lgeb

ra 1

Practi

ce

Usin

g t

he D

istr

ibu

tive P

rop

ert

y

Fa

cto

r e

ach

po

lyn

om

ial.

1. 64 -

40ab

2. 4d

2 +

16

3. 6r2t

- 3rt

2

8(8

- 5

ab

) 4

(d2 +

4)

3rt

(2r -

t)

4. 15ad

+ 3

0a

2d

2

5. 32a

2 +

24b

2

6. 36xy

2 -

48x

2y

15

ad

(1 +

2ad

) 8

(4a

2 +

3b

2)

12

xy(3

y -

4x)

7. 30x

3y +

35x

2y

2

8. 9a

3d

2 -

6ad

3

9. 75b

2g

3 +

60bg

3

5x

2y(6

x +

7y)

3ad

2(3

a2 -

2d

) 1

5b

g3(5

b +

4)

10. 8p

2r2

- 2

4pr3

+ 1

6pr

11. 5x

3y

2 +

10x

2y +

25x

12. 9ax

3 +

18bx

2 +

24cx

8p

r(p

r -

3r2

+ 2

) 5

x(x

2y

2 +

2xy +

5)

3x(3

ax

2 +

6b

x +

8c)

13. x

2 +

4x +

2x +

8

14. 2a

2 +

3a

+ 6a

+ 9

15. 4b

2 -

12b +

2b

- 6

(x +

2)(

x +

4)

(a +

3)(

2a +

3)

(4b

+ 2

)(b

- 3

)

16. 6xy -

8x +

15y -

20

17.

-6mp

+ 4m

+ 1

8p

- 1

2

18. 12a

2 -

15ab

- 1

6a

+ 2

0b

(2x +

5)(

3y -

4)

(-

2m

+ 6

)(3

p -

2)

(3a

- 4

)(4a

- 5

b)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

yo

ur s

olu

tio

ns.

19. x(x

- 3

2)

= 0

20. 4b

(b +

4)

= 0

21. (y

- 3

)(y +

2)

= 0

{

0,

32}

{-

4,

0}

{-

2,

3}

22. (a

+ 6

)(3a

- 7

) =

0

23. (2y +

5)(y -

4)

= 0

24. (4y +

8)(

3y -

4)

= 0

{-

6,

7

3 }

{- 5

2 ,

4}

{-2,

4

3 }

25. 2z2

+ 2

0z

= 0

26. 8p

2 -

4p

= 0

27. 9x

2 =

27x

{-

10,

0}

{ 0,

1

2 }

{0,

3}

28. 18x

2 =

15x

29. 14x

2 =

-21x

30. 8x

2 =

-26x

{0

, 5

6 }

{- 3

2 ,

0}

{- 1

3

4 ,

0}

31. LA

ND

SC

APIN

G A

lan

dsc

ap

ing c

om

pan

y h

as

been

com

mis

sion

ed

to d

esi

gn

a t

rian

gu

lar

flow

er

bed

for

a m

all

en

tran

ce.

Th

e f

inal

dim

en

sion

s of

the f

low

er

bed

have n

ot

been

d

ete

rmin

ed

, bu

t th

e c

om

pan

y k

now

s th

at

the h

eig

ht

wil

l be t

wo f

eet

less

th

an

th

e b

ase

.

Th

e a

rea o

f th

e f

low

er

bed

can

be r

ep

rese

nte

d b

y t

he e

qu

ati

on

A =

1

2 b

2 -

b.

a.

Wri

te t

his

equ

ati

on

in

fact

ore

d f

orm

. A

= b

( 1 −

2 b

- 1)

b.

Su

pp

ose

th

e b

ase

of

the f

low

er

bed

is

16 f

eet.

Wh

at

wil

l be i

ts a

rea?

112 f

t2

32. PH

YSIC

AL S

CIE

NC

E M

r. A

lim

’s s

cien

ce c

lass

lau

nch

ed

a t

oy r

ock

et

from

gro

un

d l

evel

wit

h a

n i

nit

ial

up

ward

velo

city

of

60 f

eet

per

seco

nd

. T

he h

eig

ht h

of

the r

ock

et

in f

eet

above t

he g

rou

nd

aft

er t

seco

nd

s is

mod

ele

d b

y t

he e

qu

ati

on

h =

60t

- 1

6t2

. H

ow

lon

g

was

the r

ock

et

in t

he a

ir b

efo

re i

t re

turn

ed

to t

he g

rou

nd

? 3.7

5 s

8-2

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-2

Ch

ap

ter

8

15

Gle

ncoe A

lgeb

ra 1

Wo

rd

Pro

ble

m P

racti

ce

Usin

g t

he D

istr

ibu

tive P

rop

ert

y

1. PH

YSIC

S A

ccord

ing t

o l

egen

d,

Gali

leo

dro

pp

ed

obje

cts

of

dif

fere

nt

weig

hts

fro

m

the s

o-c

all

ed

“le

an

ing t

ow

er”

of

Pis

a

wh

ile d

evelo

pin

g h

is f

orm

ula

for

free

fall

ing o

bje

cts.

Th

e r

ela

tion

ship

th

at

he

dis

covere

d w

as

that

the d

ista

nce

d a

n

obje

ct f

all

s aft

er t

seco

nd

s is

giv

en

by

d=

16t2

(ig

nori

ng a

ir r

esi

stan

ce).

Th

is

rela

tion

ship

can

be f

ou

nd

in

th

e e

qu

ati

on

h

= 4t

- 1

6t2

, w

here

h i

s th

e h

eig

ht

of

an

obje

ct t

hro

wn

up

ward

fro

m g

rou

nd

level

at

a r

ate

of

32 f

eet

per

seco

nd

. S

olv

e t

he

equ

ati

on

for h

= 0

. t =

0.2

5 a

nd

0

2. SW

IMM

ING

PO

OL T

he a

rea A

of

a

rect

an

gu

lar

swim

min

g p

ool

is g

iven

by

the e

qu

ati

on

A=

12w

-w

2,

wh

ere

w i

s th

e w

idth

of

on

e s

ide.

Wri

te a

n

exp

ress

ion

for

the o

ther

sid

e o

f th

e

pool.

12 -

w

3. C

ON

STR

UC

TIO

N U

niq

ue B

uil

din

g

Com

pan

y i

s co

nst

ruct

ing a

tri

an

gu

lar

roof

tru

ss f

or

a b

uil

din

g.

Th

e w

ork

ers

ass

em

ble

th

e t

russ

wit

h t

he d

imen

sion

s sh

ow

n o

n t

he d

iagra

m b

elo

w.

Usi

ng t

he

Pyth

agore

an

Th

eore

m,

fin

d t

he l

en

gth

of

the s

ides

of

the t

russ

. 3 y

d,

4 y

d,

5 y

d

4. V

ER

TIC

AL J

UM

P Y

ou

r vert

ical

jum

p

heig

ht

is m

easu

red

by s

ubtr

act

ing

you

r st

an

din

g r

each

heig

ht

from

th

e

heig

ht

of

the h

igh

est

poin

t you

can

reach

by j

um

pin

g w

ith

ou

t ta

kin

g a

ru

nn

ing

start

. T

yp

icall

y,

NB

A p

layers

have

vert

ical

jum

p h

eig

hts

of

up

to 3

4 i

nch

es.

If

an

NB

A p

layer

jum

ps

this

hig

h,

his

h

eig

ht h

in

in

ches

above h

is s

tan

din

g

reach

heig

ht

aft

er t

seco

nd

s ca

n b

e

mod

ele

d b

y t

he e

qu

ati

on

h

= 1

62t

- 1

92t2

. S

olv

e t

he e

qu

ati

on

for

h=

0 a

nd

in

terp

ret

the s

olu

tion

. R

ou

nd

you

r an

swer

to t

he n

eare

st h

un

dre

dth

.

t=

0 a

nd

t≈

0.8

44;

Th

e p

layer

lan

ds a

fter

ab

ou

t 0.8

4 s

eco

nd

s.

5. PETS

C

on

ner

toss

es

a d

og t

reat

up

ward

w

ith

an

in

itia

l velo

city

of

13.7

mete

rs p

er

seco

nd

. T

he h

eig

ht

of

the t

reat

above t

he

dog’s

mou

th h

in

mete

rs a

fter t

seco

nd

s is

giv

en

by t

he e

qu

ati

on

.h

= 1

3.7t

- 4

.9t2

a

. A

ssu

min

g t

he d

og d

oesn

’t j

um

p,

aft

er

how

man

y s

eco

nd

s d

oes

the d

og c

atc

h

the t

reat?

2.7

95

b. T

he d

og t

reat

reach

es

its

maxim

um

h

eig

ht

half

way b

etw

een

wh

en

it

was

thro

wn

an

d w

hen

it

was

cau

gh

t. W

hat

is i

ts m

axim

um

heig

ht?

9.6

m

c. H

ow

fast

wou

ld C

on

nor

have t

o t

hro

w

the d

og t

reat

in o

rder

to m

ak

e i

t fl

y

thro

ugh

th

e a

ir f

or

6 s

eco

nd

s?

at

29.4

m/s

2x -

1 y

d

x +

1 y

d

x y

d

8-2

Answers (Lesson 8-2)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A7 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

16

Gle

ncoe A

lgeb

ra 1

Lin

ear

Co

mb

inati

on

sT

he g

reate

st c

om

mon

fact

or,

GC

F,

of

two n

um

bers

can

be w

ritt

en

as

a l

inear

com

bin

ati

on

of

the t

wo n

um

bers

. A

lin

ear

com

bin

ati

on

is

an

exp

ress

ion

of

the f

orm

Ax +

By.

W

rit

e t

he g

rea

test

co

mm

on

fa

cto

r o

f 52 a

nd

36 a

s a

lin

ea

r

co

mb

ina

tio

n.

Fir

st,

use

th

e E

ucl

idean

Alg

ori

thm

to f

ind

th

e g

reate

st c

om

mon

fact

or

of

the t

wo n

um

bers

.

1

36 """""

""""""""

52

D

ivid

e t

he g

reate

r num

ber

by t

he lesser

num

ber.

36

2

16 """"

"""""""""

36

ori

gin

al

div

isor;

T

hen d

ivid

e u

sin

g t

he r

em

ain

der

as t

he n

ew

div

isor.

32

4

4 """"

"""""""""

16

se

con

d d

ivis

or;

D

ivid

e a

gain

.

16

0

Sto

p d

ivid

ing.

Last

div

isor

use

d i

s th

e G

CF

. In

th

is c

ase

, 4 i

s th

e G

CF

for

36 a

nd

52.

To w

rite

4 a

s a l

inear

com

bin

ati

on

of

36 a

nd

52,

it n

eed

s to

be w

ritt

en

as:

4 =

36

x +

52y,

wh

ere

x a

nd

y a

re s

om

e i

nte

gers

.

Use

tri

al

an

d e

rror

to d

ete

rmin

e t

he t

wo i

nte

gers

.

Th

e t

wo i

nte

gers

th

at

work

are

x =

3 a

nd

y =

-2.

So,

the l

inear

com

bin

ati

on

for

the g

reate

st

com

mon

fact

or

of

52 a

nd

36 i

s:

4 =

36(3

) +

52(-

2)

Exerc

ises

Writ

e t

he g

rea

test

co

mm

on

fa

cto

r f

or e

ach

pa

ir o

f n

um

bers a

s a

lin

ea

r

co

mb

ina

tio

n.

1. 16,

64

2. 21,

28

16 =

16(1

) +

64(0

)

7 =

21(-

1) +

28(1

)

3. 3,

18

4. 15,

36

3 =

3(1

) +

18(0

) 3

= 1

5(5

) -

36(2

)

5. 6,

8

6. 18,

42

2 =

6(-

1) +

8(1

)

6 =

18(-

2) +

42(1

)

En

rich

men

t8-2 Exam

ple

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-3

Ch

ap

ter

8

17

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

Qu

ad

rati

c E

qu

ati

on

s:

x2 +

bx +

c =

0

Facto

r x

2 +

bx +

c

To f

act

or

a t

rin

om

ial

of

the f

orm

x2 +

bx +

c,

fin

d t

wo i

nte

gers

, m

an

d p

, w

hose

su

m i

s equ

al

to b

an

d w

hose

pro

du

ct i

s equ

al

to c

.

F

acto

r e

ach

po

lyn

om

ial.

a. x

2 +

7x

+ 1

0

In

th

is t

rin

om

ial,

b =

7 a

nd

c =

10.

Facto

rs o

f 10

Su

m o

f F

acto

rs

1,

10

11

2,

57

S

ince

2 +

5 =

7 a

nd

2 #

5 =

10,

let

m =

2

an

d p

= 5

.

x

2 +

7x +

10 =

(x +

5)(

x +

2)

b. x

2 -

8x

+ 7

In t

his

tri

nom

ial,

b =

-8 a

nd

c =

7.

Noti

ce t

hat

m +

p i

s n

egati

ve a

nd

mp

is

posi

tive,

so m

an

d p

are

both

negati

ve.

Sin

ce -

7 +

(-

1)

= -

8 a

nd

(-

7)(

-1)

= 7

, m

= -

7 a

nd

p =

-1.

x2 -

8x +

7 =

(x -

7)(

x -

1)

F

acto

r x

2 +

6x

- 1

6.

In t

his

tri

nom

ial,

b =

6 a

nd

c =

-16.

Th

is

mean

s m

+ p

is

posi

tive a

nd

mp

is

negati

ve.

Mak

e a

lis

t of

the f

act

ors

of

-16,

wh

ere

on

e

fact

or

of

each

pair

is

posi

tive.

Facto

rs o

f -

16

Su

m o

f F

acto

rs

1, -

16

-15

-1,

16

15

2, -

8-

6

-2,

86

Th

ere

fore

, m

= -

2 a

nd

p =

8.

x2 +

6x -

16 =

(x -

2)(

x +

8)

Exerc

ises

Fa

cto

r e

ach

po

lyn

om

ial.

1. x

2 +

4x +

3

2. m

2 +

12m

+ 3

2

3. r2

- 3

r +

2

(

x +

3)(

x +

1)

(m

+ 4

)(m

+ 8

) (

r -

2)(

r -

1)

4. x

2 -

x -

6

5. x

2 -

4x -

21

6. x

2 -

22

x +

121

(

x -

3)(

x +

2)

(x -

7)(

x +

3)

(x -

11)(

x -

11)

7. t2

- 4

t -

12

8. p

2 -

16p

+ 6

4

9. 9 -

10

x +

x2

(

t +

2)(

t -

6)

(p

- 8

)(p

- 8

) (

9 -

x)(

1 -

x)

10. x

2 +

6x +

5

11. a

2 +

8a

- 9

12. y

2 -

7y -

8

(

x +

5)(

x +

1)

(a

- 1

)(a +

9)

(y -

8)(

y +

1)

13. x

2 -

2x -

3

14. y

2 +

14

y +

13

15. m

2 +

9m

+ 2

0

(

x -

3)(

x +

1)

(y +

1)(

y +

13)

(m

+ 4

)(m

+ 5

)

16. x

2 +

12

x +

20

17. a

2 -

14a

+ 2

4

18. 18 +

11

y +

y2

(

x +

10)(

x +

2)

(a

- 2

)(a -

12)

(9 +

y)(

2 +

y)

19. x

2 +

2xy +

y2

20. a

2 -

4a

b +

4b

2

21. x

2 +

6xy -

7y

2

(

x +

y)(

x +

y)

(a

- 2

b)(

a -

2b

) (

x +

7y)(

x -

y)

8-3

Exam

ple

1Exam

ple

2

Facto

rin

g x

2 +

bx +

cx

2 +

bx +

c =

(x +

m)(

x +

p),

where

m +

p =

b a

nd m

p =

c.

Answers (Lesson 8-2 and Lesson 8-3)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A8 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

18

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

(con

tin

ued

)

Qu

ad

rati

c E

qu

ati

on

s:

x2 +

bx +

c =

0

So

lve E

qu

ati

on

s b

y F

act

ori

ng

F

act

ori

ng a

nd

th

e Z

ero

Pro

du

ct P

rop

ert

y c

an

be u

sed

to

solv

e m

an

y e

qu

ati

on

s of

the f

orm

x2 +

bx +

c =

0.

S

olv

e x

2 +

6x

= 7

. C

heck

yo

ur s

olu

tio

ns.

x

2 +

6x =

7

Origin

al equation

x

2 +

6x -

7 =

0

Rew

rite

equation s

o t

hat

one s

ide e

quals

0.

(x

- 1

)(x +

7) =

0

Facto

r.

x -

1 =

0 or

x +

7 =

0

Zero

Pro

duct

Pro

pert

y

x =

1

x =

-7

Solv

e e

ach e

quation.

Th

e s

olu

tion

set

is {

1, -

7}.

Sin

ce 1

2 +

6 =

7 a

nd

(-

7)2

+ 6

(-7) =

7,

the s

olu

tion

s ch

eck

.

R

OC

KET L

AU

NC

H A

ro

ck

et

is f

ired

wit

h a

n i

nit

ial

velo

cit

y o

f 2288

feet

per s

eco

nd

. H

ow

ma

ny

seco

nd

s w

ill

it t

ak

e f

or t

he r

ock

et

to h

it t

he g

ro

un

d?

Th

e f

orm

ula

h =

vt -

16t2

giv

es

the h

eig

ht

h o

f th

e r

ock

et

aft

er

t se

con

ds

wh

en

th

e i

nit

ial

velo

city

v i

s giv

en

in

feet

per

seco

nd

.

h

= v

t -

16t2

F

orm

ula

0 =

2288

t -

16

t2

Substitu

te.

0 =

16

t(143 -

t)

Facto

r.

16t =

0 or

143 -

t =

0

Zero

Pro

duct

Pro

pert

y

t =

0

t =

143

Solv

e e

ach e

quation.

Th

e v

alu

e t

= 0

rep

rese

nts

th

e t

ime a

t la

un

ch.

Th

e r

ock

et

retu

rns

to t

he g

rou

nd

in

143

seco

nd

s, o

r a l

ittl

e l

ess

th

an

2.5

min

ute

s aft

er

lau

nch

.

Exerc

ises

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

1. x

2 -

4x +

3 =

0 {1

, 3}

2. y

2 -

5y +

4 =

0 {1

, 4}

3. m

2 +

10m

+ 9

= 0

4. x

2 =

x +

2 {-

1,

2}

5. x

2 -

4x =

5 {-

1,

5}

6. x

2 -

12

x +

36 =

0 {6}

7. t2

- 8

= -

7t {-

8, 1}

8. p

2 =

9p -

14 {2

, 7}

9. -

9 -

8x +

x2 =

0 {-

1, 9}

10. x

2 +

6 =

5x {2,

3}

11. a

2 =

11a

- 1

8 {2,

9}

12. y

2 -

8y +

15

= 0

{3,

5}

13. x

2 =

24 -

10

x {-

12,

2}

14. a

2 -

18a

= -

72 {6,

12}

15. b

2 =

10b

- 1

6 {2,

8}

Use t

he f

orm

ula

h =

vt -

16t

2 t

o s

olv

e e

ach

pro

ble

m.

16. FO

OTB

ALL A

pu

nte

r ca

n k

ick

a f

ootb

all

wit

h a

n i

nit

ial

velo

city

of

48 f

eet

per

seco

nd

. H

ow

man

y s

eco

nd

s w

ill

it t

ak

e f

or

the b

all

to r

etu

rn t

o t

he g

rou

nd

? 3 s

eco

nd

s

17. B

ASEB

ALL A

ball

is

thro

wn

up

wit

h a

n i

nit

ial

velo

city

of

32 f

eet

per

seco

nd

. H

ow

man

y

seco

nd

s w

ill

it t

ak

e f

or

the b

all

to r

etu

rn t

o t

he g

rou

nd

? 2 s

eco

nd

s

18. R

OC

KET L

AU

NC

H If

a r

ock

et

is l

au

nch

ed

wit

h a

n i

nit

ial

velo

city

of

1600 f

eet

per

seco

nd

, w

hen

wil

l th

e r

ock

et

be 1

4,4

00 f

eet

hig

h?

at

10 s

eco

nd

s a

nd

at

90 s

eco

nd

s

8-3

Exam

ple

1

Exam

ple

2

{-1, -

9}

Lesson 8-3

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Sk

ills

Pra

ctic

e

Qu

ad

rati

c E

qu

ati

on

s:

x2 +

bx +

c =

0

Fa

cto

r e

ach

po

lyn

om

ial.

1. t2

+ 8

t +

12

2. n

2 +

7n

+ 1

2

(

t +

2)(

t +

6)

(n

+ 3

)(n

+ 4

)

3. p

2 +

9p

+ 2

0

4. h

2 +

9h

+ 1

8

(

p +

5)(

p +

4)

(h

+ 6

)(h

+ 3

)

5. n

2 +

3n

- 1

8

6. x

2 +

2x -

8

(

n +

6)(

n -

3)

(x +

4)(

x -

2)

7. y

2 -

5y -

6

8. g

2 +

3g -

10

(

y +

1)(

y -

6)

(g

+ 5

)(g

- 2

)

9. r2

+ 4

r -

12

10. x

2 -

x -

12

(

r -

2)(

r +

6)

(x -

4)(

x +

3)

11. w

2 -

w -

6

12. y

2 -

6y +

8

(

w -

3)(

w +

2)

(y -

2)(

y -

4)

13. x

2 -

8x +

15

14. b

2 -

9b

+ 8

(

x -

5)(

x -

3)

(b

- 1

)(b

- 8

)

15. t2

- 1

5t +

56

16. -

4 -

3m

+ m

2

(

t -

7)(

t -

8)

(m

- 4

)(m

+ 1

)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

17. x

2 -

6x +

8 =

0 {2,

4}

18. b

2 -

7b

+ 1

2 =

0 {3,

4}

19. m

2 +

5m

+ 6

= 0

{-

3, -

2}

20. d

2 +

7d

+ 1

0 =

0 {-

5, -

2}

21. y

2 -

2y -

24

= 0

{-

4,

6}

22. p

2 -

3p

= 1

8 {-

3,

6}

23. h

2 +

2h

= 3

5 {-

7,

5}

24. a

2 +

14a

= -

45 {-

9, -

5}

25. n

2 -

36 =

5n

{-

4,

9}

26. w

2 +

30

= 1

1w

{5,

6}

8-3

Ch

ap

ter

8

19

Gle

ncoe A

lgeb

ra 1

Answers (Lesson 8-3)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A9 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

20

Gle

ncoe A

lgeb

ra 1

Practi

ce

Qu

ad

rati

c E

qu

ati

on

s:

x2 +

bx +

c =

0

Fa

cto

r e

ach

po

lyn

om

ial.

1. a

2 +

10a

+ 2

4

2. h

2 +

12h

+ 2

7

3. x

2 +

14

x +

33

(a +

4)(

a +

6)

(h

+ 3

)(h

+ 9

) (

x +

11)(

x +

3)

4. g

2 -

2g -

63

5. w

2 +

w -

56

6. y

2 +

4y -

60

(g +

7)(

g -

9)

(w

+ 8

)(w

- 7

) (

y +

10)(

y -

6)

7. b

2 +

4b

- 3

2

8. n

2 -

3n

- 2

8

9. t2

+ 4

t -

45

(b -

4)(

b +

8)

(n

- 7

)(n

+ 4

) (

t -

5)(

t +

9)

10. z2

- 1

1z +

30

11. d

2 -

16d

+ 6

3

12. x

2 -

11

x +

24

(z -

6)(

z -

5)

(d

- 9

)(d

- 7

) (

x -

3)(

x -

8)

13. q

2 -

q -

56

14. x

2 -

6x -

55

15. 32 +

18r +

r2

(q -

8)(

q +

7)

(x +

5)(

x -

11)

(r +

16)(

r +

2)

16. 48 -

16g +

g2

17. j 2

- 9

jk -

10

k2

18. m

2 -

mv -

56v

2

(g -

12)(

g -

4)

( j -

10

k)(

j +

k)

(m

- 8

v)(

m +

7v)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

19. x

2 +

17x +

42

= 0

20. p

2 +

5p

- 8

4 =

0

21. k

2 +

3k -

54 =

0{-

14, -

3}

{-

12,

7}

{-

9,

6}

22. b

2 -

12

b -

64 =

0

23. n

2 +

4n

= 3

2

24. h

2 -

17h

= -

60

{-

4,

16}

{-

8,

4}

{5,

12}

25. t2

- 2

6t =

56

26. z2

- 1

4z =

72

27. y

2 -

84

= 5

y

{-

2,

28}

{-

4,

18}

{-

7,

12}

28. 80 +

a2 =

18a

29. u

2 =

16u

+ 3

6

30. 17

r +

r2 =

-52

{8,

10}

{-

2,

18}

{-

13, -

4}

31. F

ind

all

valu

es

of

k s

o t

hat

the t

rin

om

ial

x2 +

kx -

35 c

an

be f

act

ore

d u

sin

g i

nte

gers

. -

34, -

2,

2,

34

32. C

ON

STR

UC

TIO

N A

con

stru

ctio

n c

om

pan

y i

s p

lan

nin

g t

o p

ou

r co

ncr

ete

for

a d

rivew

ay.

Th

e l

en

gth

of

the d

rivew

ay i

s 16 f

eet

lon

ger

than

its

wid

th w

.

a.

Wri

te a

n e

xp

ress

ion

for

the a

rea o

f th

e d

rivew

ay.

w(w

+ 1

6)

ft 2

b.

Fin

d t

he d

imen

sion

s of

the d

rivew

ay i

f it

has

an

are

a o

f 260 s

qu

are

feet.

10 f

t b

y 2

6 f

t

32. W

EB

DESIG

N Jan

eel

has

a 1

0-i

nch

by 1

2-i

nch

ph

oto

gra

ph

. S

he w

an

ts t

o s

can

th

e

ph

oto

gra

ph

, th

en

red

uce

th

e r

esu

lt b

y t

he s

am

e a

mou

nt

in e

ach

dim

en

sion

to p

ost

on

her

Web s

ite.

Jan

eel

wan

ts t

he a

rea o

f th

e i

mage t

o b

e o

ne e

igh

th t

hat

of

the o

rigin

al

ph

oto

gra

ph

.

a.

Wri

te a

n e

qu

ati

on

to r

ep

rese

nt

the a

rea o

f th

e r

ed

uce

d i

mage.

(10 -

x)(

12 -

x) =

15,

or

x2 -

22x +

105 =

0

b.

Fin

d t

he d

imen

sion

s of

the r

ed

uce

d i

mage.

3 i

n.

by 5

in

.

8-3

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-3

Ch

ap

ter

8

21

Gle

ncoe A

lgeb

ra 1

1. C

OM

PA

CT D

ISC

S A

sta

nd

ard

jew

el

case

fo

r a c

om

pact

dis

c h

as

a w

idth

2 c

m

gre

ate

r th

an

its

len

gth

. T

he a

rea f

or

the

fron

t co

ver

is 1

68 s

qu

are

cen

tim

ete

rs.

Th

e f

irst

tw

o s

tep

s to

fin

din

g t

he v

alu

e o

f x a

re s

how

n b

elo

w.

Solv

e t

he e

qu

ati

on

an

d f

ind

th

e l

en

gth

of

the c

ase

.

Len

gth

×w

idth = a

rea

x(x + 2

) = 1

68

x2 + 2

x - 1

68 = 0

-14 o

r 12;

12 c

m

2. M

ATH

GA

MES

F

ion

a a

nd

Gre

g p

lay a

n

um

ber

gu

ess

ing g

am

e.

Gre

g g

ives

Fio

na

this

hin

t abou

t h

is t

wo s

ecr

et

nu

mbers

, “T

he p

rod

uct

of

the t

wo c

on

secu

tive

posi

tive i

nte

gers

th

at

I am

th

ink

ing o

f is

11 m

ore

th

an

th

eir

su

m.”

Wh

at

are

G

reg’s

nu

mbers

? 4 a

nd

5

3. B

RID

GE E

NG

INEER

ING

A

car

dri

vin

g

over

a s

usp

en

sion

bri

dge i

s su

pp

ort

ed

by

a c

able

han

gin

g b

etw

een

th

e e

nd

s of

the

bri

dge.

Sin

ce i

ts s

hap

e i

s p

ara

boli

c, i

t ca

n

be m

od

ele

d b

y a

qu

ad

rati

c equ

ati

on

. T

he

heig

ht

above t

he r

oad

bed

of

a b

rid

ge’s

ca

ble

h (

in i

nch

es)

measu

red

at

dis

tan

ce

d (

in y

ard

s) f

rom

th

e f

irst

tow

er

is g

iven

by t

he e

qu

ati

on

h=

d2-

36d+

324.

If t

he d

river

of

a c

ar

look

s ou

t at

a h

eig

ht

of

49 i

nch

es

above t

he r

oad

bed

, at

wh

at

dis

tan

ce(s

) fr

om

th

e t

ow

er

wil

l th

e

dri

ver’

s eyes

be a

t th

e s

am

e h

eig

ht

as

the

cable

? at

11 a

nd

25 y

ds f

rom

th

e

firs

t to

wer

4. PH

YSIC

AL S

CIE

NC

E T

he b

oil

ing p

oin

t of

wate

r d

ep

en

ds

on

alt

itu

de.

Th

e f

oll

ow

ing

equ

ati

on

ap

pro

xim

ate

s th

e n

um

ber

of

degre

es

D b

elo

w 2

12ºF

at

wh

ich

wate

r w

ill

boil

at

alt

itu

de h

.

D2+

520

D=

H

In D

en

ver,

Colo

rad

o,

the a

ltit

ud

e i

s ap

pro

xim

ate

ly 5

300 f

eet

above s

ea l

evel.

A

t ap

pro

xim

ate

ly w

hat

tem

pera

ture

does

wate

r boil

in

Den

ver?

D=

10°

dro

p T

he b

oilin

g p

oin

t is

ab

ou

t 202°F

.

5. M

ON

UM

EN

TS

Su

san

is

desi

gn

ing a

p

yra

mid

al

ston

e m

on

um

en

t fo

r a l

oca

l p

ark

. T

he d

esi

gn

sp

eci

fica

tion

s te

ll h

er

that

the h

eig

ht

need

s to

be 9

feet,

th

e

wid

th o

f th

e b

ase

mu

st b

e 5

feet

less

th

an

th

e l

en

gth

, an

d t

he v

olu

me s

hou

ld

be 1

50 c

ubic

feet.

Reca

ll t

hat

the

volu

me o

f a p

yra

mid

is

giv

en

by V

= 1 − 3

Bh

,

wh

ere

B i

s th

e a

rea o

f th

e b

ase

an

d h

is

the h

eig

ht.

a.

Wri

te a

nd

solv

e a

n e

qu

ati

on

to f

ind

th

e

wid

th o

f th

e b

ase

of

the m

on

um

en

t.

150 =

1 − 3w

(w+

5) ·

9 o

r

3w

2+

15

w-

150 =

0;

w=

{5, -

10}

b.

Inte

rpre

t each

an

swer

in t

erm

s of

the

situ

ati

on

. w=

5:

the w

idth

of

the

pyra

mid

is 5

feet;

w=-

10:

neg

ati

ve l

en

gth

do

esn

’t m

ake

sen

se i

n t

he s

itu

ati

on

.

Wo

rd

Pro

ble

m P

racti

ce

Qu

ad

rati

c E

qu

ati

on

s:

x2 +

bx +

c =

0

d

h

8-3

Answers (Lesson 8-3)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A10 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

22

Gle

ncoe A

lgeb

ra 1

En

rich

men

t

Pu

zzlin

g P

rim

es

A p

rim

e n

um

ber

has

on

ly t

wo f

act

ors

, it

self

an

d 1

. T

he n

um

ber

6 i

s n

ot

pri

me b

eca

use

it

has

2 a

nd

3 a

s fa

ctors

; 5 a

nd

7 a

re p

rim

e.

Th

e n

um

ber

1 i

s n

ot

con

sid

ere

d t

o b

e p

rim

e.

1. U

se a

calc

ula

tor

to h

elp

you

fin

d t

he 2

5 p

rim

e n

um

bers

less

th

an

100.

2

, 3,

5,

7,

11,

13,

17,

19,

23,

29,

31,

37 4

1,

43,

47,

53,

59,

61,

67,

71,

73,

79,

83,

89,

97

Pri

me n

um

bers

have i

nte

rest

ed

math

em

ati

cian

s fo

r ce

ntu

ries.

Th

ey h

ave t

ried

to f

ind

exp

ress

ion

s th

at

wil

l giv

e a

ll t

he p

rim

e n

um

bers

, or

on

ly p

rim

e n

um

bers

. In

th

e 1

700s,

E

ule

r d

isco

vere

d t

hat

the t

rin

om

ial

x2 +

x +

41 w

ill

yie

ld p

rim

e n

um

bers

for

valu

es

of

x

from

0 t

hro

ugh

39.

2. F

ind

th

e p

rim

e n

um

bers

gen

era

ted

by E

ule

r’s

form

ula

for

x f

rom

0 t

hro

ugh

7.

4

1,

43,

47,

53,

61,

71,

83,

97

3. S

how

th

at

the t

rin

om

ial

x2 +

x +

31 w

ill

not

giv

e p

rim

e n

um

bers

for

very

man

y v

alu

es

of

x.

I

t w

ork

s f

or

x =

0,

2,

3,

5,

an

d 6

bu

t n

ot

for

x =

1,

4,

an

d 7

.

4. F

ind

th

e l

arg

est

pri

me n

um

ber

gen

era

ted

by E

ule

r’s

form

ula

.

1601

Gold

ba

ch’s

Con

ject

ure

is

that

every

non

zero

even

nu

mber

gre

ate

r th

an

2 c

an

be w

ritt

en

as

the s

um

of

two p

rim

es.

No o

ne h

as

ever

pro

ved

th

at

this

is

alw

ays

tru

e,

bu

t n

o o

ne h

as

fou

nd

a c

ou

nte

rexam

ple

, eit

her.

5. S

how

th

at

Gold

bach

’s C

on

ject

ure

is

tru

e f

or

the f

irst

5 e

ven

nu

mbers

gre

ate

r th

an

2.

4

= 2

+ 2

, 6 =

3 +

3,

8 =

3 +

5,

10

= 3

+ 7

, 12 =

5 +

7

6. G

ive a

way t

hat

som

eon

e c

ou

ld d

isp

rove G

old

bach

’s C

on

ject

ure

.

F

ind

an

even

nu

mb

er

that

can

no

t b

e w

ritt

en

as t

he s

um

of

two

pri

mes.

8-3

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-4

Ch

ap

ter

8

23

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

Qu

ad

rati

c E

qu

ati

on

s:

ax

2 +

bx +

c =

0

Facto

r ax

2 +

bx

+ c

T

o f

act

or

a t

rin

om

ial

of

the f

orm

ax

2 +

bx +

c,

fin

d t

wo i

nte

gers

, m

an

d p

wh

ose

pro

du

ct i

s equ

al

to a

c an

d w

hose

su

m i

s equ

al

to b

. If

th

ere

are

no i

nte

gers

th

at

sati

sfy t

hese

requ

irem

en

ts,

the p

oly

nom

ial

is c

all

ed

a p

rim

e p

oly

no

mia

l.

F

acto

r 2x

2 +

15x +

18.

In t

his

exam

ple

, a

= 2

, b

= 1

5,

an

d c

= 1

8.

You

need

to f

ind

tw

o n

um

bers

th

at

have a

su

m o

f 15 a

nd

a p

rod

uct

of

2

18 o

r 36.

Mak

e a

lis

t of

the f

act

ors

of

36 a

nd

look

for

the p

air

of

fact

ors

wit

h a

su

m o

f 15.

Facto

rs o

f 36

Su

m o

f F

acto

rs

1,

36

37

2,

18

20

3,

12

15

U

se t

he p

att

ern

ax

2 +

mx +

px +

c,

wit

h

a

= 2

, m

= 3

, p

= 1

2,

an

d c

= 1

8.

2

x2 +

15x +

18 =

2x

2 +

3x +

12x +

18

= (

2x

2 +

3x) +

(1

2x +

18)

= x

(2x +

3) +

6(2

x +

3)

= (

x +

6)(

2x +

3)

Th

ere

fore

, 2x

2 +

15x +

18 =

(x +

6)(

2x +

3).

F

acto

r 3x

2 -

3x -

18.

Note

th

at

the G

CF

of

the t

erm

s 3

x2,

3x,

an

d 1

8 i

s 3.

Fir

st f

act

or

ou

t th

is G

CF

.

3x

2 -

3x -

18 =

3(x

2 -

x -

6).

Now

fact

or

x2 -

x -

6.

Sin

ce a

= 1

, fi

nd

th

e

two f

act

ors

of -

6 w

ith

a s

um

of -

1.

Facto

rs o

f -

6S

um

of

Facto

rs

1, -

6-

5

-1,

65

-2,

31

2, -

3-

1

Now

use

th

e p

att

ern

(x +

m)(

x +

p)

wit

h

m =

2 a

nd

p =

-3.

x2 -

x -

6 =

(x +

2)(

x -

3)

Th

e c

om

ple

te f

act

ori

zati

on

is

3x

2 -

3x -

18 =

3(x

+ 2

)(x -

3).

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

usin

g

inte

gers,

writ

e prim

e.

1. 2

x2 -

3x -

2

2. 3

m2 -

8m

- 3

3. 16

r2 -

8r

+ 1

(

2x +

1)(

x -

2)

(3

m +

1)(

m -

3)

(4

r -

1)(

4r -

1)

4. 6

x2 +

5x -

6

5. 3

x2 +

2x -

8

6. 18

x2 -

27

x -

5

(

2x +

3)(

3x -

2)

(3

x -

4)(

x +

2)

(3

x -

5)(

6x +

1)

7. 2

a2 +

5a

+ 3

8. 18

y2 +

9y -

5

9. -

4t2

+ 1

9t -

21

(

2a

+ 3

)(a

+ 1

) (

6y +

5)(

3y -

1)

(4t -

7)(

3 -

t)

10. 8

x2 -

4x -

24

11. 28

p2 +

60p

- 2

5

12. 48x

2 +

22

x -

15

(

4x -

8)(

2x +

3)

(2

p +

5)(

14p

- 5

) (

6x +

5)(

8x -

3)

13. 3y

2 -

6y -

24

14. 4

x2 +

26x -

48

15. 8

m2 -

44

m +

48

3

(y +

2)(

y -

4)

2(x

+ 8

)(2x -

3)

4(2

m -

3)(

m -

4)

16. 6x

2 -

7x +

18

17. 2

a2 -

14

a +

18

18. 18 +

11y +

2y

2

p

rim

e

2(a

2 -

7a +

9)

pri

me

8-4

Exam

ple

1Exam

ple

2

Exerc

ises

Answers (Lesson 8-3 and Lesson 8-4)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A11 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

24

Gle

ncoe A

lgeb

ra 1

So

lve E

qu

ati

on

s b

y F

act

ori

ng

F

act

ori

ng a

nd

th

e Z

ero

Pro

du

ct P

rop

ert

y c

an

be u

sed

to

solv

e s

om

e e

qu

ati

on

s of

the f

orm

ax

2 +

bx +

c =

0.

S

olv

e 1

2x

2 +

3x =

2 -

2x

. C

heck

yo

ur s

olu

tio

ns.

12

x2 +

3x =

2 -

2x

Origin

al equation

12x

2 +

5x -

2 =

0

Rew

rite

equation s

o t

hat

one s

ide e

quals

0.

(3

x +

2)(

4x -

1)

= 0

F

acto

r th

e left s

ide.

3

x +

2 =

0 o

r 4

x -

1 =

0

Zero

Pro

duct

Pro

pert

y

x =

- 2

3

x =

1

4

Solv

e e

ach e

quation.

Th

e s

olu

tion

set

is {-

2

3 ,

1

4 } .

Sin

ce 1

2 (-

2

3 ) 2

+ 3

(- 2

3 ) =

2 -

2 (-

2

3 ) a

nd

12 ( 1

4 ) 2

+ 3

( 1

4 ) =

2 -

2 ( 1

4 ) ,

the s

olu

tion

s ch

eck

.

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

1. 8x

2 +

2x -

3 =

0

2. 3n

2 -

2n

- 5

= 0

3. 2

d2 -

13

d -

7 =

0

{

1

2 , -

3

4 }

{-

1,

5

3 }

{-

1

2 ,

7}

4. 4

x2 =

x +

3

5. 3x

2 -

13x =

10

6. 6

x2 -

11x -

10 =

0

{

1, -

3

4 }

{-

2

3 ,

5}

{-

2

3 ,

5

2 }

7. 2

k2 -

40 =

-11k

8. 2p

2 =

-21p

- 4

0

9.

-7 -

18x +

9x

2 =

0

{-

8,

5

2 }

{-

5

2 , -

8}

{ 7

3 , -

1

3 }

10. 12x

2 -

15 =

-8

x

11. 7a

2 =

-65a

- 1

8

12. 16

y2 -

2y -

3 =

0

{- 3

2 ,

5

6 }

{-

2

7 , -

9 }

{ 1

2 , -

3

8 }

13. 8

x2 +

5x =

3 +

7x

14. 4a

2 -

18

a +

5 =

15

15. 3

b2 -

18

b =

10b

- 4

9

{ 3

4 , -

1

2 }

{-

1

2 ,

5}

{ 7

3 ,

7}

16. T

he d

iffe

ren

ce o

f th

e s

qu

are

s of

two c

on

secu

tive o

dd

in

tegers

is

24.

Fin

d t

he i

nte

gers

. -

5, -

7 a

nd

5,

7

17. G

EO

METR

Y T

he l

en

gth

of

a C

harl

ott

e,

Nort

h C

aro

lin

a,

con

serv

ato

ry g

ard

en

is

20 y

ard

s gre

ate

r th

an

its

wid

th.

Th

e a

rea i

s 300 s

qu

are

yard

s. W

hat

are

th

e d

imen

sion

s?

30 y

d b

y 1

0 y

d

18. G

EO

METR

Y A

rect

an

gle

wit

h a

n a

rea o

f 24 s

qu

are

in

ches

is

fo

rmed

by c

utt

ing s

trip

s of

equ

al

wid

th f

rom

a r

ect

an

gu

lar

pie

ce

of

pap

er.

Fin

d t

he d

imen

sion

s of

the n

ew

rect

an

gle

if

the o

rigin

al

rect

an

gle

measu

res

8 i

nch

es

by 6

in

ches.

6 i

n.

by 4

in

.

8 in

.

x

6 in

.

x

x x

8-4 Exam

ple

Exerc

ises

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

(con

tin

ued

)

Qu

ad

rati

c E

qu

ati

on

s:

ax

2 +

bx +

c =

0

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-4

Ch

ap

ter

8

25

Gle

ncoe A

lgeb

ra 1

Sk

ills

Pra

ctic

e

Qu

ad

rati

c E

qu

ati

on

s:

ax

2 +

bx +

c =

0

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

usin

g

inte

gers,

writ

e prim

e.

1. 2

x2 +

5x +

2

2. 3n

2 +

5n

+ 2

(

x +

2)(

2x +

1)

(3

n +

2)(

n +

1)

3. 2

t2 +

9t

- 5

4. 3g

2 -

7g +

2

(

t +

5)(

2t -

1)

(3

g -

1)(

g -

2)

5. 2

t2 -

11t

+ 1

5

6. 2x

2 +

3x -

6

(

t -

3)(

2t -

5)

pri

me

7. 2

y2 +

y -

1

8. 4

h2 +

8h

- 5

(

y +

1)(

2y -

1)

(2

h +

5)(

2h

- 1

)

9. 4

x2 -

3x -

3

10. 4

b2 +

15b

- 4

p

rim

e

(4

b -

1)(

b +

4)

11. 9

p2 +

6p

- 8

12. 6

q2 -

13q

+ 6

(

3p

- 2

)(3p

+ 4

) (

3q

- 2

)(2q

- 3

)

13. 3

a2 +

30a

+ 6

3

14. 10w

2 -

19w

- 1

5

3

(a +

7)(

a +

3)

(2w

- 5

)(5

w +

3)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

15. 2x

2 +

7x +

3 =

0 {-

3, - 1

2 }

16. 3w

2 +

14w

+ 8

= 0

{-

4, -

2

3 }

17. 3

n2 -

7n

+ 2

= 0

{ 1

3 ,

2}

18. 5d

2 -

22

d +

8 =

0 { 2

5 ,

4}

19. 6

h2 +

8h

+ 2

= 0

{-

1, -

1

3 }

20. 8

p2 -

16

p =

10 {-

1

2 ,

5

2 }

21. 9

y2 +

18y -

12 =

6y {-

2,

2

3 }

22. 4

a2 -

16

a =

-15 { 3

2 ,

5

2 }

23. 10

b2 -

15

b =

8b -

12 { 4

5 ,

3

2 }

24. 6

d2 +

21d

= 1

0d

+ 3

5 {-

7

2 ,

5

3 }

8-4

Answers (Lesson 8-4)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A12 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

26

Gle

ncoe A

lgeb

ra 1

Practi

ce

Qu

ad

rati

c E

qu

ati

on

s:

ax

2 +

bx +

c =

0

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

usin

g

inte

gers,

writ

e prim

e.

1. 2b

2 +

10b

+ 1

2

2. 3g

2 +

8g +

4

3. 4x

2 +

4x -

3

2

(b +

2)(

b +

3)

(3

g +

2)(

g +

2)

(2x +

3)(

2x -

1)

4. 8b

2 -

5b -

10

5. 6m

2 +

7m

- 3

6. 10d

2 +

17d

- 2

0

p

rim

e

(3m

- 1

)(2m

+ 3

) (

5d

- 4

)(2

d +

5)

7. 6a

2 -

17a

+ 1

2

8. 8w

2 -

18w

+ 9

9. 10x

2 -

9x +

6

(

3a

- 4

)(2

a -

3)

(4

w -

3)(

2w

- 3

) p

rim

e

10. 15n

2 -

n -

28

11. 10x

2 +

21x -

10

12. 9r2

+ 1

5r

+ 6

(

5n

- 7

)(3

n +

4)

(2x +

5)(

5x -

2)

3(3

r +

2)(

r +

1)

13. 12y

2 -

4y -

5

14. 14k

2 -

9k

- 1

8

15. 8z2

+ 2

0z

- 4

8

(

2y +

1)(

6y -

5)

(2

k -

3)(

7k

+ 6

) 4

(z +

4)(

2z -

3)

16. 12q

2 +

34q

- 2

8

17. 18h

2 +

15h

- 1

8

18. 12p

2 -

22p

- 2

0

2

(3q

- 2

)(2

q +

7)

3(2

h +

3)(

3h

- 2

) 2

(3p

+ 2

)(2

p -

5)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

19. 3h

2 +

2h

- 1

6 =

0

20. 15n

2 -

n =

2

21. 8q

2 -

10q +

3 =

0

{-

8

3 ,

2}

{-

1

3 ,

2

5 }

{ 1

2 ,

3

4 }

22. 6b

2 -

5b =

4

23. 10r2

- 2

1r

= -

4r

+ 6

24. 10g

2 +

10 =

29g

{-

1

2 ,

4

3 }

{-

3

10 ,

2}

{ 2

5 ,

5

2 }

25. 6y

2 =

-7y -

2

26. 9z2

= -

6z

+ 1

5

27. 12k

2 +

15k

= 1

6k +

20

{-

2

3 , -

1

2 }

{-

5

3 ,

1}

{-

5

4 ,

4

3 }

28. 12x

2 -

1 =

-x

29. 8a

2 -

16a

= 6a

- 1

2

30. 18a

2 +

10a

= -

11a

+ 4

{-

1

3 ,

1

4 }

{ 3

4 ,

2}

{-

4

3 ,

1

6 }

31. D

IVIN

G L

au

ren

dove i

nto

a s

wim

min

g p

ool

from

a 1

5-f

oot-

hig

h d

ivin

g b

oard

wit

h a

n

init

ial

up

ward

velo

city

of

8 f

eet

per

seco

nd

. F

ind

th

e t

ime t

in

seco

nd

s it

took

Lau

ren

to

en

ter

the w

ate

r. U

se t

he m

od

el

for

vert

ical

moti

on

giv

en

by t

he e

qu

ati

on

h

= -

16t2

+ vt

+ s

, w

here

h i

s h

eig

ht

in f

eet,

t i

s ti

me i

n s

eco

nd

s, v

is

the i

nit

ial

up

ward

velo

city

in

feet

per

seco

nd

, an

d s

is

the i

nit

ial

heig

ht

in f

eet.

(Hint:

Let h

= 0

rep

rese

nt

the s

urf

ace

of

the p

ool.

) 1.2

5 s

32. B

ASEB

ALL B

rad

toss

ed

a b

ase

ball

in

th

e a

ir f

rom

a h

eig

ht

of

6 f

eet

wit

h a

n i

nit

ial

up

ward

velo

city

of

14 f

eet

per

seco

nd

. E

nri

qu

e c

au

gh

t th

e b

all

on

its

way d

ow

n a

t a p

oin

t 4 f

eet

above t

he g

rou

nd

. H

ow

lon

g w

as

the b

all

in

th

e a

ir b

efo

re E

nri

qu

e c

au

gh

t it

? U

se

the m

od

el

of

vert

ical

moti

on

fro

m E

xerc

ise 3

1.

1 s

8-4

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-4

Ch

ap

ter

8

27

Gle

ncoe A

lgeb

ra 1

Wo

rd

Pro

ble

m P

racti

ce

Qu

ad

rati

c E

qu

ati

on

s:

ax

2 +

bx +

c =

0

1. B

REA

K E

VEN

B

reak

ing e

ven

occ

urs

w

hen

th

e r

even

ues

for

a b

usi

ness

equ

al

the c

ost

. A

loca

l ch

ild

ren

’s m

use

um

st

ud

ied

th

eir

cost

s (w

ages,

ele

ctri

city

, etc

.) a

nd

reven

ues

from

paid

ad

mis

sion

. T

hey f

ou

nd

th

at

their

bre

ak

-even

tim

e i

s giv

en

by t

he e

qu

ati

on

2h

2-

2h

- 2

4 =

0,

wh

ere

h i

s th

e n

um

ber

of

hou

rs t

he

mu

seu

m i

s op

en

per

day.

How

man

y

hou

rs m

ust

th

e m

use

um

be o

pen

per

day

to r

each

th

e b

reak

even

poin

t?

4 h

ou

rs

2. C

AR

PEN

TR

Y M

iko w

an

ts t

o b

uil

d a

toy

box f

or

her

sist

er.

It

is t

o b

e 2

feet

hig

h,

an

d t

he w

idth

is

to b

e 3

feet

less

th

an

its

le

ngth

. If

it

need

s to

hold

a v

olu

me o

f 80 c

ubic

feet,

fin

d t

he l

en

gth

an

d w

idth

of

the b

ox.

len

gth

= 8

ft;

wid

th =

5 f

t

3. FU

RN

ITU

RE

T

he s

tud

en

t co

un

cil

wan

ts

to p

urc

hase

a t

able

for

the s

chool

lobby.

Th

e t

able

com

es

in a

vari

ety

of

dim

en

sion

s, b

ut

for

every

table

, th

e

len

gth

is

1 m

ete

r gre

ate

r th

an

tw

ice t

he

wid

th.

Th

e s

tud

en

t co

un

cil

has

bu

dgete

d

for

a t

able

top

wit

h a

n a

rea o

f exact

ly

3 s

qu

are

mete

rs.

Fin

d t

he w

idth

an

d l

en

gth

of

the t

able

th

ey c

an

pu

rch

ase

. w

idth

= 1

m;

len

gth

= 3

m

4. LA

DD

ER

S A

lad

der

is r

est

ing a

gain

st a

w

all

. T

he t

op

of

the l

ad

der

tou

ches

the

wall

at

a h

eig

ht

of

15 f

eet,

an

d t

he l

en

gth

of

the l

ad

der

is o

ne f

oot

more

th

an

tw

ice

its

dis

tan

ce f

rom

th

e w

all

. F

ind

th

e

dis

tan

ce f

rom

th

e w

all

to t

he b

ott

om

of

the l

ad

der.

(Hint:

Use

th

e P

yth

agore

an

T

heore

m t

o s

olv

e t

he p

roble

m.)

8 f

t

15 ft.

Wall

Ladder

5. FA

RM

ING

M

r. H

en

sley h

as

a t

ota

l of

480 s

qu

are

feet

of

sheet

meta

l w

ith

w

hic

h h

e w

ou

ld l

ike t

o c

on

stru

ct a

cy

lin

dri

cal

tan

k f

or

stori

ng g

rain

. T

he

loca

l zon

ing l

aw

lim

its

the h

eig

ht

of

the

tan

k t

o 1

3.5

feet.

Reca

ll t

hat

a f

orm

ula

fo

r th

e s

urf

ace

are

a o

f a b

ott

om

less

cy

lin

der

wit

h r

ad

ius r

an

d h

eig

ht h

is

A =

πr2

+ 2

πrh

.

a.

Wri

te a

qu

ad

rati

c equ

ati

on

(se

t equ

al

to z

ero

) to

rep

rese

nt

the i

nfo

rmati

on

.

0 =

πr2

+ 2

r -

480

b.

Usi

ng 3

as

an

ap

pro

xim

ati

on

for

π,

solv

e t

he e

qu

ati

on

for r.

{5

, -

32}

c.

Wh

at

rad

ius

shou

ld M

r. H

en

sley u

se

for

his

tan

k?

5 f

t

8-4

2w

+1

w

Answers (Lesson 8-4)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A13 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

28

Gle

ncoe A

lgeb

ra 1

En

rich

men

t

Are

a M

od

els

fo

r Q

uad

rati

c T

rin

om

ials

Aft

er

you

have f

act

ore

d a

qu

ad

rati

c tr

inom

ial,

you

can

use

th

e f

act

ors

to

dra

w g

eom

etr

ic m

od

els

of

the t

rin

om

ial.

x

2 +

5x -

6 =

(x -

1)(

x +

6)

To d

raw

a r

ect

an

gu

lar

mod

el,

th

e v

alu

e 2

w

as

use

d f

or

x s

o t

hat

the s

hort

er

sid

e w

ou

ld

have a

len

gth

of

1.

Th

en

th

e d

raw

ing w

as

don

e i

n c

en

tim

ete

rs.

So,

the a

rea o

f th

e

rect

an

gle

is

x2 +

5x -

6.

To d

raw

a r

igh

t tr

ian

gle

mod

el,

reca

ll t

hat

th

e a

rea o

f a t

rian

gle

is

on

e-h

alf

th

e b

ase

ti

mes

the h

eig

ht.

So,

on

e o

f th

e s

ides

mu

st

be t

wic

e a

s lo

ng a

s th

e s

hort

er

sid

e o

f th

e

rect

an

gu

lar

mod

el.

x2 +

5x -

6 =

(x -

1)(

x +

6)

= 1

2 (

2x -

2)(

x +

6)

Th

e a

rea o

f th

e r

igh

t tr

ian

gle

is

als

o x

2 +

5x -

6.

Fa

cto

r e

ach

trin

om

ial.

Th

en

fo

llo

w t

he d

irecti

on

s t

o d

ra

w e

ach

mo

del

of

the t

rin

om

ial.

1. x

2 +

2x -

3 U

se x

= 2

. D

raw

a

2. 3

x2 +

5x -

2 U

se x

= 1

. D

raw

a

rect

an

gle

in

cen

tim

ete

rs.

re

ctan

gle

in

cen

tim

ete

rs.

(x

+ 2

)(3x -

1)

(

x +

3)(

x -

1)

3. x

2 -

4x +

3 U

se x

= 4

. D

raw

tw

o d

iffe

ren

t ri

gh

t tr

ian

gle

s in

cen

tim

ete

rs.

(x

- 1

)(x -

3)

4. 9

x2 -

9x +

2 U

se x

= 2

. D

raw

tw

o d

iffe

ren

t ri

gh

t tr

ian

gle

s.

Use

0.5

cen

tim

ete

r fo

r each

un

it.

(3x -

2)(

3x -

1)

3x

- 2

6x

- 2

3x

- 1

6x

- 4

2x

- 6

x-

1

x-

3

2x

- 2

3x

- 1

x+

2

x-

1

x+

3

x+

6

2x

- 2

x+

6

x-

1

8-4

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-4

Ch

ap

ter

8

29

Gle

ncoe A

lgeb

ra 1

Gra

ph

ing C

alc

ula

tor

Act

ivit

y

Usin

g T

ab

les i

n F

acto

rin

g b

y G

rou

pin

g

Th

e T

AB

LE f

eatu

re c

an

be u

sed

to h

elp

fact

or

a p

oly

nom

ial

by f

ind

ing t

he f

act

ors

of

a c

ert

ain

p

rod

uct

, w

hic

h h

ave a

sp

eci

fic

sum

.

F

acto

r 1

0x

2-

43x

+ 2

8 b

y g

ro

up

ing

.

Mak

e a

table

of

the n

egati

ve f

act

ors

of

10

! 2

8 o

r 280.

Look

for

a p

air

of

fact

ors

wh

ose

su

m i

s -

43.

En

ter

the e

qu

ati

on

y =

280

x

in

Y1 t

o f

ind

th

e f

act

ors

of

280.

Th

en

,

fin

d t

he s

um

of

the f

act

ors

usi

ng y

= 2

80

x

+ x

in

Y2.

Set

up

th

e t

able

to d

isp

lay t

he n

egati

ve f

act

ors

of

280 b

y s

ett

ing ∆

Tb

l =

to

-1.

Exam

ine t

he r

esu

lts.

Th

e l

ast

lin

e o

f th

e t

able

sh

ow

s th

at

-43x m

ay b

e r

ep

lace

d w

ith

-

8x

+ (

-35x).

10x

2 -

43x +

28 =

10x

2 -

8x +

(-

35

x)

+ 2

8

=

2x(5

x -

4)

+ (

-7)(

5x -

4)

=

(5

x -

4)(

2x -

7)

Th

us,

10

x2 -

43

x +

28 =

(5x -

4)(

2x -

7).

F

acto

r 1

2x

2 -

7x -

12.

Look

at

the f

act

ors

of

12

! -

12 o

r -

144 f

or

a p

air

wh

ose

su

m i

s -

7.

En

ter

an

equ

ati

on

to d

ete

rmin

e t

he f

act

ors

in

Y1 a

nd

an

equ

ati

on

to

fin

d t

he s

um

of

fact

ors

in

Y2.

Exam

ine t

he t

able

to f

ind

a s

um

of

-7.

12x

2 -

7x -

12

= 1

2x

2 +

9x +

(-

16x)

- 1

2

= 3

x(4

x +

3)

- 4

(4x +

3)

=

(4

x +

3)(

3x -

4)

Th

us,

12x

2 -

7x -

12 =

(4

x +

3)(

3x -

4).

Fa

cto

r e

ach

qu

ad

ra

tic p

oly

no

mia

l if

po

ssib

le.

1. x

2 +

29

x -

96

2. x

2 -

14

x -

51

3. 3

z2 +

16z

- 3

5

(y +

32)(

y -

3)

(x -

17)(

x +

3)

(3

z -

5)(

z +

7)

4. 4

y2 -

25y +

18

5. 6a

2 -

a -

15

6. 6m

2 +

13m

+ 6

p

rim

e

(3a

- 5

)(2a

+ 3

) (

2m

+ 3

)(3m

+ 2

)

7. 12z2

- z

- 6

8. 16y

2 +

40y +

25

9. 4b

2 +

24b

- 4

93

(

4z -

3)(

3z +

2)

(4y +

5)2

(

2b

+ 2

9)(

2b

- 1

7)

8-4

Exam

ple

1

Exam

ple

2

Exerc

ises

Answers (Lesson 8-4)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A14 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

30

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

Qu

ad

rati

c E

qu

ati

on

s:

Dif

fere

nces o

f S

qu

are

s

Fact

or

Dif

fere

nce

s o

f Sq

uare

s T

he b

inom

ial

exp

ress

ion

a2 -

b2 i

s ca

lled

th

e

dif

feren

ce o

f tw

o s

qu

ares.

Th

e f

oll

ow

ing p

att

ern

sh

ow

s h

ow

to f

act

or

the d

iffe

ren

ce o

f sq

uare

s.

F

acto

r e

ach

po

lyn

om

ial.

a. n

2 -

64

n

2 -

64

= n

2 -

82

Write

in t

he f

orm

a2 -

b2.

= (

n +

8)(

n -

8)

Facto

r.

b.

4m

2 -

81n

2

4m

2 -

81n

2

=

(2

m)2

- (

9n

)2

Write

in t

he f

orm

a2 -

b2.

=

(2

m -

9n

)(2

m +

9n

) F

acto

r.

F

acto

r e

ach

po

lyn

om

ial.

a.

50a

2 -

72

50a

2 -

72

=

2(2

5a

2 -

36)

Fin

d t

he G

CF

.

=

2[(

5a

)2 -

62)]

25

a2 =

5a

5a

and 3

6 =

6

6

=

2(5

a +

6)(

5a

- 6

) F

acto

r th

e d

iffe

rence o

f square

s.

b.

4x

4 +

8x

3 -

4x

2 -

8x

4

x4 +

8x

3 -

4x

2 -

8x

Origin

al poly

nom

ial

=

4x(x

3 +

2x

2 -

x -

2)

Fin

d t

he G

CF

.

=

4x[(

x3 +

2x

2) -

(x +

2)]

G

roup t

erm

s.

=

4x[x

2(x

+ 2

) -

1(x

+ 2

)]

Fin

d t

he G

CF

.

=

4x[(

x2 -

1)(

x +

2)]

F

acto

r by g

roupin

g.

=

4x[(

x -

1)(

x +

1)(

x +

2)]

Fa

cto

r th

e d

iffe

rence

of

square

s.

Exerc

ises

Fa

cto

r e

ach

po

lyn

om

ial.

1. x

2 -

81

2. m

2 -

100

3. 16

n2 -

25

(

x +

9)(

x -

9)

(m

+ 1

0)(

m -

10)

(4n

- 5

)(4

n +

5)

4. 36x

2 -

100

y2

5. 49x

2 -

36

6. 16

a2 -

9b

2

(

6x +

10y)(

6x -

10y)

(7x +

6)(

7x -

6)

(4a

- 3

b)(

4a

+ 3

b)

7. 225

b2 -

a2

8. 72p

2 -

50

9. -

2 +

2x

2

(

15b

- a

)(15b

+ a

) 2

(6p

+ 5

)(6p

- 5

) 2

(x -

1)(

x +

1)

10. -

81 +

a4

11. 6 -

54a

2

12. 8y

2 -

200

(

a -

3)(

a +

3)(

a2 +

9)

6(1

+ 3

a)(

1 -

3a

) 8

(y +

5)(

y -

5)

13. 4x

3 -

10

0x

14. 2y

4 -

32y

2

15. 8

m3 -

12

8m

4

x(x

+ 5

)(x -

5)

2y

2(y

+ 4

)(y -

4)

8m

(m +

4)(

m -

4)

16. 4x

2 -

25

17. 2a

3 -

98

ab

2

18. 18

y2 -

72

y4

(

2x +

5)(

2x -

5)

2a

(a -

7b

)(a

+ 7

b)

18

y2(1

- 2

y)(

1 +

2y)

19. 169x

3 -

x

20. 3

a4 -

3a

2

21. 3

x4 +

6x

3 -

3x

2 -

6x

x

(13x +

1)(

13

x -

1)

3a

2(a

+ 1

)(a

- 1

) 3

x(x

- 1

)(x +

1)(

x +

2)

8-5

Exam

ple

1Exam

ple

2

Dif

fere

nce o

f S

qu

are

sa

2 -

b2 =

(a

- b

)(a

+ b

) =

(a +

b)(

a -

b).

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-5

Ch

ap

ter

8

31

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

(con

tin

ued

)

Qu

ad

rati

c E

qu

ati

on

s:

Dif

fere

nces o

f S

qu

are

s

So

lve E

qu

ati

on

s b

y F

act

ori

ng

F

act

ori

ng a

nd

th

e Z

ero

Pro

du

ct P

rop

ert

y c

an

be u

sed

to

solv

e e

qu

ati

on

s th

at

can

be w

ritt

en

as

the p

rod

uct

of

an

y n

um

ber

of

fact

ors

set

equ

al

to 0

.

S

olv

e e

ach

eq

ua

tio

n.

Ch

eck

yo

ur s

olu

tio

ns.

a. x

2 -

1 −

25 =

0

x2 -

1

25 =

0

Origin

al equation

x2 -

( 1

5 ) 2

= 0

x

2 =

x ·

x a

nd

1

25 =

( 1

5 ) (

1

5 )

(x

+ 1

5 ) (x

- 1

5 ) =

0

Facto

r th

e d

iffe

rence o

f square

s.

x +

1

5 =

0

or

x -

1

5 =

0

Zero

Pro

duct

Pro

pert

y

x =

- 1

5

x =

1

5

Solv

e e

ach e

quation.

Th

e s

olu

tion

set

is {-

1

5 ,

1

5 } .

Sin

ce (-

1

5 ) 2

-

1

25 =

0 a

nd

( 1

5 ) 2

-

1

25 =

0,

the s

olu

tion

s ch

eck

.

b.

4x

3 =

9x

4

x3 =

9x

Origin

al equation

4x

3 -

9x =

0

Subtr

act

9x f

rom

each s

ide.

x(4

x2 -

9) =

0

Fin

d t

he G

CF

.

x[(

2x)2

- 3

2] =

0

4x

2 =

2x

2x a

nd 9

= 3

3

x[(

2x)2

- 3

2] =

x[(

2x -

3)(

2x +

3)]

F

acto

r th

e d

iffe

rence o

f square

s.

x =

0 or

(2

x -

3) =

0 or

(2

x +

3) =

0

Zero

Pro

duct

Pro

pert

y

x =

0

x =

3

2

x =

- 3

2

Solv

e e

ach e

quation.

Th

e s

olu

tion

set

is {0

, 3

2 , -

3

2 } .

Sin

ce 4

(0)3

= 9

(0),

4 ( 3

2 ) 3

= 9

( 3

2 ) ,

an

d 4

(- 3

2 ) 3

= 9

(- 3

2 ) ,

the s

olu

tion

s ch

eck

.

So

lve e

ach

eq

ua

tio

n b

y f

acto

rin

g.

Ch

eck

th

e s

olu

tio

ns.

1. 81

x2 =

49 { 7

9 , -

7 −

9 }

2. 36n

2 =

1 {-

1 −

6 ,

1 −

6 }

3. 25

d2 -

100 =

0 {2

, -

2}

4. 1

4 x

2 =

25

{1

0, -

10}

5. 36 =

1

25 x

2 {-

30,

30}

6. 4

9

100 -

x2

= 0

{-

7 −

10 ,

7 −

10 }

7. 9

x3 =

25x {0

, -

5 −

3 ,

5 −

3 }

8. 7

a3 =

175a

{0

, -

5,

5}

9. 2

m3 =

32m

{0

, -

4,

4}

10. 16y

3 =

25y {0

, -

5 −

4 ,

5 −

4 }

11. 1

64 x

2 =

49 {-

56,

56}

12. 4

a3 -

64a

= 0

{0

, -

4,

4}

13. 3

b3 -

27b

= 0

{0

, -

3,

3}

14. 9

25 m

2 =

121 {-

55 −

3 ,

55 −

3 }

15. 48n

3 =

147

n {0

, -

7 −

4 ,

7 −

4 }

8-5

Exerc

ises

Exam

ple

Answers (Lesson 8-5)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A15 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

32

Gle

ncoe A

lgeb

ra 1

Sk

ills

Practi

ce

Qu

ad

rati

c E

qu

ati

on

s:

Dif

fere

nces o

f S

qu

are

s

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

,

writ

e prim

e.

1. a

2 -

4

2. n

2 -

64

(

a +

2)(

a -

2)

(n

+ 8

)(n

- 8

)

3. 1 -

49

d2

4. -

16 +

p2

(

1 +

7d

)(1 -

7d

) (

p +

4)(

p -

4)

5. k

2 +

25

6. 36 -

100w

2

p

rim

e

(6 -

10

w)(

6 +

10w

)

7. t2

- 8

1u

2

8. 4

h2 -

25

g2

(

t +

9u

)(t -

9u

) (

2h

+ 5

g)(

2h

- 5

g)

9. 64m

2 -

9y

2

10. 4

c2 -

5d

2

(

8m

- 3

y)(

8m

+ 3

y)

pri

me

11. -

49r2

+ 4

t2

12. 8

x2 -

72p

2

(

2t +

7r)

(2t -

7r)

8

(x +

3p

)(x -

3p

)

13. 20q

2 -

5r2

14. 32a

2 -

50b

2

5

(2q

+ r

)(2

q -

r)

2(4

a +

5b

)(4

a -

5b

)

So

lve e

ach

eq

ua

tio

n b

y f

acto

rin

g.

Ch

eck

th

e s

olu

tio

ns.

15. 16x

2 -

9 =

0 {±

3

4 }

16. 25p

2 -

16 =

0 {±

4

5 }

17. 36q

2 -

49

= 0

7

6 }

18. 81 -

4b

2 =

0 {±

9

2 }

19. 16d

2 =

4 {±

1

2 }

20. 18a

2 =

8 {±

2

3 }

21. n

2 -

9

25 =

0 {±

3

5 }

22. k

2 -

49 −

64 =

0 {±

7

8 }

23. 1

25 h

2 -

16 =

0 {±

20}

24. 1

16 y

2 =

81 {±

36}

8-5

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-5

Ch

ap

ter

8

33

Gle

ncoe A

lgeb

ra 1

Practi

ce

Qu

ad

rati

c E

qu

ati

on

s:

Dif

fere

nces o

f S

qu

are

s

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

, w

rit

e

prim

e.

1. k

2 -

10

0

2. 81 -

r2

3. 16

p2 -

36

(

k +

10)(

k -

10)

(9 +

r)(

9 -

r)

(4

p +

6)(

4p

- 6

)

4. 4x

2 +

25

5. 144 -

9f 2

6. 36

g2 -

49

h2

p

rim

e

(12 +

3f)(

12 -

3f)

(6

g +

7h

)(6g

- 7

h)

7. 121m

2 -

14

4p

2

8. 32 -

8y

2

9. 24

a2 -

54

b2

(

11m

- 1

2p

)(11

m +

12p

) 8

(2 -

y)(

2 +

y)

6(2

a -

3b

)(2a

+ 3

b)

10. 32t2

- 1

8u

2

11. 9d

2 -

32

12. 36z3

- 9

z

2

(4t -

3u

)(4t +

3u

) p

rim

e

9z

(2z +

1)(

2z -

1)

13. 45q

3 -

20q

14. 100

b3 -

36

b

15. 3

t4 -

48t2

5

q(3

q +

2)(

3q

- 2

) 4

b(5

b +

3)(

5b

- 3

) 3

t2(t

+ 4

)(t -

4)

So

lve e

ach

eq

ua

tio

n b

y f

acto

rin

g.

Ch

eck

yo

ur s

olu

tio

ns.

16. 4y

2 =

81

17. 64p

2 =

9

18. 98b

2 -

50 =

0

{± 9

2 }

{± 3

8 }

{± 5

7 }

19. 32 -

162

k2 =

0

20. t2

-

64 −

121 =

0

21. 1

6 −

49 -

v2 =

0

{± 4

9 }

{± 8

11 }

{± 4

7 }

22.

1 −

36 x

2 -

25 =

0

23. 27h

3 =

48h

24. 75

g3 =

14

7g

30}

{± 4

3 ,

0}

{± 7

5 ,

0}

25. ER

OSIO

N A

rock

bre

ak

s lo

ose

fro

m a

cli

ff a

nd

plu

nges

tow

ard

th

e g

rou

nd

400 f

eet

belo

w.

Th

e d

ista

nce

d t

hat

the r

ock

fall

s in

t s

eco

nd

s is

giv

en

by t

he e

qu

ati

on

d =

16t2

.

How

lon

g d

oes

it t

ak

e t

he r

ock

to h

it t

he g

rou

nd

? 5 s

26. FO

REN

SIC

S M

r. C

oop

er

con

test

ed

a s

peed

ing t

ick

et

giv

en

to h

im a

fter

he a

pp

lied

his

bra

kes

an

d s

kid

ded

to a

halt

to a

void

hit

tin

g a

noth

er

car.

In

tra

ffic

cou

rt,

he a

rgu

ed

th

at

the l

en

gth

of

the s

kid

mark

s on

th

e p

avem

en

t, 1

50 f

eet,

pro

ved

th

at

he w

as

dri

vin

g

un

der

the p

ost

ed

sp

eed

lim

it o

f 65 m

iles

per

hou

r. T

he t

ick

et

cite

d h

is s

peed

at

70 m

iles

per

hou

r. U

se t

he f

orm

ula

1 −

24 s

2 =

d,

wh

ere

s i

s th

e s

peed

of

the c

ar

an

d d

is

the l

en

gth

of

the s

kid

mark

s, t

o d

ete

rmin

e M

r. C

oop

er’

s sp

eed

wh

en

he a

pp

lied

th

e b

rak

es.

Was

Mr.

Coop

er

corr

ect

in

cla

imin

g t

hat

he w

as

not

speed

ing w

hen

he a

pp

lied

th

e b

rak

es?

60 m

ph

; yes

8-5

Answers (Lesson 8-5)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A16 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

34

Gle

ncoe A

lgeb

ra 1

Wo

rd

Pro

ble

m P

racti

ce

Qu

ad

rati

c E

qu

ati

on

s:

Dif

fere

nces o

f S

qu

are

s

1. LO

TTER

Y A

sta

te l

ott

ery

com

mis

sion

an

aly

zes

the t

ick

et

pu

rch

asi

ng p

att

ern

s of

its

citi

zen

s. T

he f

oll

ow

ing e

xp

ress

ion

is

develo

ped

to h

elp

off

icia

ls c

alc

ula

te t

he

lik

ely

nu

mber

of

peop

le w

ho w

ill

bu

y

tick

ets

for

a c

ert

ain

siz

e j

ack

pot.

81

a2-

36

b2

Fact

or

the e

xp

ress

ion

com

ple

tely

.

3(3

a+

2b

) (3

a-

2b

)

2. O

PTIC

S A

refl

ect

or

on

th

e i

nsi

de o

f a

cert

ain

fla

shli

gh

t is

a p

ara

bola

giv

en

by

the e

qu

ati

on

y=

x2-

25.

Fin

d t

he p

oin

ts

wh

ere

th

e r

efl

ect

or

meets

th

e l

en

s by

fin

din

g t

he v

alu

es

of

x w

hen

y=

0.

5, -

5

3. A

RC

HIT

EC

TU

RE

T

he d

raw

ing s

how

s a

tria

ngu

lar

roof

tru

ss w

ith

a b

ase

m

easu

rin

g t

he s

am

e a

s it

s h

eig

ht.

Th

e

are

a o

f th

e t

russ

is

98 s

qu

are

mete

rs.

Fin

d t

he h

eig

ht

of

the t

russ

. 14 m

4. B

ALLO

ON

ING

T

he f

un

ctio

n

f (t)

=-

16t2+

576 r

ep

rese

nts

th

e h

eig

ht

of

a f

reely

fall

ing b

all

ast

bag t

hat

start

s fr

om

rest

on

a b

all

oon

576 f

eet

above t

he

gro

un

d.

Aft

er

how

man

y s

eco

nd

s t

does

the b

all

ast

bag h

it t

he g

rou

nd

?

aft

er

6 s

eco

nd

s

5. D

EC

OR

ATIN

G M

arv

in w

an

ts t

o

pu

rch

ase

a r

ect

an

gu

lar

rug.

It h

as

an

are

a o

f 80 s

qu

are

feet.

He c

an

not

rem

em

ber

the l

en

gth

an

d w

idth

, bu

t h

e

rem

em

bers

th

at

the l

en

gth

was

8 m

ore

th

an

som

e n

um

ber

an

d t

he w

idth

was

8 l

ess

th

an

th

at

sam

e n

um

ber.

a

. Wri

te a

qu

ad

rati

c equ

ati

on

usi

ng t

he

info

rmati

on

giv

en

. x

2-

64 =

80 o

r x

2-

144 =

0

b

. Wh

at

are

th

e l

en

gth

an

d w

idth

of

the

rug?

20 f

t an

d 4

ft

Are

a =

98m

2he

ight

base

x+

8

x-

8

8-5

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-5

Ch

ap

ter

8

35

Gle

ncoe A

lgeb

ra 1

En

ric

hm

en

t

Facto

rin

g T

rin

om

ials

of

Fo

urt

h D

eg

ree

Som

e t

rin

om

ials

of

the f

orm

a4 +

a2b

2 +

b4 c

an

be w

ritt

en

as

the

dif

fere

nce

of

two s

qu

are

s an

d t

hen

fact

ore

d.

F

acto

r 4x

4 -

37x

2y

2 +

9y

4.

Ste

p 1

F

ind

th

e s

qu

are

roots

of

the f

irst

an

d l

ast

term

s.

√ ""

4x

4 =

2x

2

√ ""

9y

4 =

3y

2

Ste

p 2

F

ind

tw

ice t

he p

rod

uct

of

the s

qu

are

roots

.

2(2

x2)(

3y

2) =

12

x2y

2

Ste

p 3

S

ep

ara

te t

he m

idd

le t

erm

in

to t

wo p

art

s. O

ne p

art

is

eit

her

you

r an

swer

to S

tep

2 o

r it

s op

posi

te.

Th

e o

ther

part

sh

ou

ld b

e

the o

pp

osi

te o

f a p

erf

ect

squ

are

.

-

37x

2y

2 =

-12x

2y

2 -

25x

2y

2

Ste

p 4

R

ew

rite

th

e t

rin

om

ial

as

the d

iffe

ren

ce o

f tw

o s

qu

are

s an

d

then

fact

or.

4x

4 -

37x

2y

2 +

9y

4 =

(4

x4 -

12x

2y

2 +

9y

4) -

25x

2y

2

= (

2x

2 -

3y

2)2

- 2

5x

2y

2

= [

(2x

2 -

3y

2) +

5xy][

(2x

2 -

3y

2) -

5xy]

= (

2x

2 +

5xy -

3y

2)(

2x

2 -

5xy -

3y

2)

Fa

cto

r e

ach

po

lyn

om

ial.

1. x

4 +

x2y

2 +

y4

2. x

4 +

x2 +

1

(

x2 + x

y +

y2)(

x2 -

xy +

y2)

(x

2 +

x +

1)(

x2 -

x +

1)

3. 9

a4 -

15a

2 +

1

4. 16a

4 -

17a

2 +

1

(

3a

2 +

3a

- 1

)(3

a2 -

3a -

1)

(4

a -

1)(

a +

1)(

4a

+ 1

)(a

- 1

)

5. 4

a4 -

13a

2 +

1

6. 9

a4 +

26a

2b

2 +

25

b4

(

2a

2 +

3a -

1)(

2a

2 -

3a -

1)

(3

a2 +

2ab

+ 5

b2)(

3a

2 -

2ab

+ 5

b2)

7. 4

x4 -

21x

2y

2 +

9y

4

8. 4

a4 -

29a

2b

2 +

25

b4

(

2x

2 +

3xy -

3y

2)(

2x

2 -

3xy -

3y

2)

(2

a +

5b

)(a

- b

)(2

a -

5b

)(a

+ b

)

8-5 Exam

ple

Answers (Lesson 8-5)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A17 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

36

Gle

ncoe A

lgeb

ra 1

Sp

read

sheet

Act

ivit

y

Dif

fere

nces o

f S

qu

are

s

Th

ere

is

a s

peci

al

patt

ern

you

can

use

to f

act

or

bin

om

ials

of

the f

orm

a2 -

b2.

You

can

use

a s

pre

ad

sheet

to d

isco

ver

this

rela

tion

ship

.

U

se a

sp

rea

dsh

eet

to i

nv

esti

ga

te t

he v

alu

es o

f th

e e

xp

ress

ion

s (a

2 -

b2),

(a

- b

)2, (a

- b

)(a

+ b

), a

nd

(a

+ b

)2. W

ha

t co

nje

ctu

re c

an

yo

u m

ak

e a

bo

ut

the e

xp

ressio

ns?

Ste

p 1

Y

ou

wil

l u

se C

olu

mn

s A

an

d B

to e

nte

r vari

ou

s valu

es

that

you

ch

oose

for a

an

d b

.

Ste

p 2

E

nte

r th

e f

orm

ula

s fo

r (a

2 -

b2),

(a

- b

)2,

(a -

b)(a

+ b

), a

nd

(a

+ b

)2

in C

olu

mn

s C

, D

, E

, an

d F

. T

o e

nte

r an

exp

on

en

t, u

se t

he s

ym

bol

^

foll

ow

ed

by t

he e

xp

on

en

t. F

or

exam

ple

, th

e s

qu

are

of

the v

alu

e i

n

cell

A2 i

s en

tere

d a

s A

2^

2.

1. E

nte

r vari

ou

s valu

es

of a

an

d b

in

Colu

mn

s A

an

d B

. L

ook

for

a p

att

ern

. W

hat

do y

ou

obse

rve a

bou

t th

e e

xp

ress

ion

s? F

or

an

y v

alu

es o

f a

an

d b

, (a

2 -

b2) =

(a -

b)(

a +

b).

2. F

ind

th

e p

rod

uct

s of

(a -

b)2

, (a

- b

)(a

+ b

), a

nd

(a

+ b

)2.

Do t

he r

esu

lts

veri

fy y

ou

r co

nje

ctu

re?

(a -

b)2

= a

2 -

2ab

+ b

2;

(a -

b)(

a +

b) =

a

2 -

b2;

an

d (

a +

b)2

= a

2 +

2ab

+ b

2;

yes

Use t

he p

att

ern

yo

u o

bserv

ed

to

fa

cto

r e

ach

bin

om

ial.

3. m

2 -

t2

4. x

2 -

4

5. y

2 -

16

(

m -

t)(

m +

t)

(x -

2)(

x +

2)

(y -

4)(

y +

4)

6. q

2 -

121

7. r2

- 1

69

8. b

2 -

1

(q

- 1

1)(

q +

11)

(r -

13)(

r +

13)

(b

- 1

)(b

+ 1

)

9. 4x

2 -

1

10. 16t2

- r

2

11. 25a

2 -

81d

2

(

2x -

1)(

2x +

1)

(4

t -

r)(

4t +

r)

(5a

- 9

d)(

5a +

9d

)

A

1 2 3 4 5

BC

DE

Fa^

2 -

b^

2(a

- b

)(a +

b)

(a -

b)^

2(a

+ b

)^2

ab

=(A

2-

B2)^

2=

A2^2-

B2^2

=(A

2-

B2)*

(A2+

B2)

=(A

2+

B2)^

2

=(A

3-

B3)^

2=

A3^2-

B3^2

=(A

3-

B3)*

(A3+

B3)

=(A

3+

B3)^

2

=(A

4-

B4)^

2=

A4^2-

B4^2

=(A

4-

B4)*

(A4+

B4)

=(A

4+

B4)^

2

Sh

eet

1S

heet

2S

heet

3

8-5

Exerc

ises

Exam

ple

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-6

Ch

ap

ter

8

37

Gle

ncoe A

lgeb

ra 1

Fact

or

Perf

ect

Sq

uare

Tri

no

mia

ls

Th

e p

att

ern

s sh

ow

n b

elo

w c

an

be u

sed

to f

act

or

perf

ect

squ

are

tri

nom

ials

.

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

Qu

ad

rati

c E

qu

ati

on

s:

Perf

ect

Sq

uare

s

D

ete

rm

ine w

heth

er

16n

2 -

24n

+ 9

is a

perfe

ct

sq

ua

re

trin

om

ial.

If

so

, fa

cto

r i

t.

Sin

ce 1

6n

2 =

(4n

)(4n

), t

he f

irst

term

is

a

perf

ect

squ

are

.

Sin

ce 9

= 3

! 3

, th

e l

ast

term

is

a p

erf

ect

sq

uare

.

Th

e m

idd

le t

erm

is

equ

al

to 2

(4n

)(3).

Th

ere

fore

, 16n

2 -

24n

+ 9

is

a p

erf

ect

sq

uare

tri

nom

ial.

16n

2 -

24n

+ 9

= (

4n

)2 -

2(4n

)(3)

+ 3

2

=

(4n

- 3

)2

F

acto

r 1

6x

2 -

32x +

15.

Sin

ce 1

5 i

s n

ot

a p

erf

ect

squ

are

, u

se a

dif

fere

nt

fact

ori

ng p

att

ern

.

16x

2 -

32x +

15

O

rigin

al tr

inom

ial

=

16x

2 +

mx +

px +

15

Write

the p

attern

.

=

16x

2 -

12x -

20x +

15

m =

-12 a

nd p

= -

20

=

(1

6x

2 -

12x)

- (

20x -

15)

Gro

up t

erm

s.

=

4x(4x -

3)

- 5

(4x -

3)

Fin

d t

he G

CF

.

=

(4x -

5)(

4x -

3)

Facto

r by g

roupin

g.

Th

ere

fore

16x

2 -

32x +

15

= (

4x -

5)(

4x -

3).

Exerc

ises

Dete

rm

ine w

heth

er e

ach

trin

om

ial

is a

perfe

ct

sq

ua

re t

rin

om

ial.

Writ

e yes o

r no

. If

so

, fa

cto

r i

t.

1. x

2 -

16x +

64

2. m

2 +

10m

+ 2

5

3. p

2 +

8p

+ 6

4

y

es;

(x -

8)(

x -

8)

yes;

(m +

5)(

m +

5)

no

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

, w

rit

e

prim

e.

4. 98x

2 -

20

0y

2

5. x

2 +

22x +

121

6. 81 +

18j

+ j

2

2

(7x +

10y)(

7x -

10

y)

(x +

11)2

(

9 +

j)2

7. 25c2

- 1

0c

- 1

8. 169 -

26r

+ r

2

9. 7x

2 -

9x +

2

p

rim

e

(13 -

r)2

(

7x -

2)(

x -

1)

10. 16m

2 +

48m

+ 3

6

11. 16 -

25a

2

12. b

2 -

16b

+ 2

56

4

(2m

+ 3

)2

(4 +

5a

)(4 -

5a

) p

rim

e

13. 36x

2 -

12x +

1

14. 16a

2 -

40ab

+ 2

5b

2

15. 8m

3 -

64m

(

6x -

1)2

(

4a

- 5

b)2

8

m(m

2 -

8)

8-6

Exam

ple

1Exam

ple

2

Perf

ect

Sq

uare

Tri

no

mia

la t

rinom

ial of

the f

orm

a2 +

2ab

+ b

2 o

r a

2 -

2ab

+ b

2

Sq

uari

ng

a B

ino

mia

lF

acto

rin

g a

Perf

ect

Sq

uare

Tri

no

mia

l

(a +

4)2

= a

2 +

2(a

)(4)

+ 4

2

=

a2 +

8a +

16

a2 +

8a +

16

= a

2 +

2(a

)(4)

+ 4

2

=

(a +

4)2

(2x -

3)2

= (

2x)2

-2(2

x)(

3)

+ 3

2

=

4x

2 -

12x +

9

4x

2 -

12x +

9 =

(2x)2

-2(2

x)(

3)

+ 3

2

=

(2x -

3)2

Answers (Lesson 8-5 and Lesson 8-6)

Co

pyrig

ht ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f Th

e M

cG

raw

-Hill C

om

pan

ies, In

c.

Chapter 8 A18 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

38

Gle

ncoe A

lgeb

ra 1

Stu

dy

Gu

ide a

nd

In

terv

en

tio

n

(con

tin

ued

)

Qu

ad

rati

c E

qu

ati

on

s:

Perf

ect

Sq

uare

s

So

lve E

qu

ati

on

s w

ith

Perf

ect

Sq

uare

s F

act

ori

ng a

nd

th

e Z

ero

Pro

du

ct P

rop

ert

y

can

be u

sed

to s

olv

e e

qu

ati

on

s th

at

involv

e r

ep

eate

d f

act

ors

. T

he r

ep

eate

d f

act

or

giv

es

just

on

e s

olu

tion

to t

he e

qu

ati

on

. Y

ou

may a

lso b

e a

ble

to u

se t

he s

qu

are r

oo

t p

ro

perty

belo

w

to s

olv

e c

ert

ain

equ

ati

on

s.

S

olv

e e

ach

eq

ua

tio

n.

Ch

eck

yo

ur s

olu

tio

ns.

a. x

2 -

6x +

9 =

0

x

2 -

6x +

9 =

0

Origin

al equation

x

2 -

2(3

x) +

32 =

0

Recogniz

e a

perf

ect

square

trinom

ial.

(x

- 3

)(x -

3) =

0

Facto

r th

e p

erf

ect

square

trinom

ial.

x -

3 =

0

Set

repeate

d f

acto

r equal to

0.

x =

3

Solv

e.

Th

e s

olu

tion

set

is {

3}.

Sin

ce 3

2 -

6(3

) +

9 =

0,

the s

olu

tion

ch

eck

s.

b.

(a -

5)2

= 6

4

(a

- 5

)2 =

64

O

rigin

al equation

a

- 5

= ± √ ##

64

Square

Root

Pro

pert

y

a

- 5

= ±

8

64 =

8 $

8

a

= 5

± 8

A

dd 5

to e

ach s

ide.

a

= 5

+ 8

or

a =

5 -

8

Separa

te into

2 e

quations.

a

= 1

3

a =

-3

Solv

e e

ach e

quation.

Th

e s

olu

tion

set

is {-

3,

13}.

Sin

ce (-

3 -

5)2

= 6

4 a

nd

(13 -

5)2

= 6

4,

the s

olu

tion

s ch

eck

.

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

1. x

2 +

4x +

4 =

0 {-

2}

2. 16n

2 +

16

n +

4 =

0 {- 1

2 }

3. 25d

2 -

10

d +

1 =

0 { 1

5 }

4. x

2 +

10x +

25

= 0

{-

5}

5. 9

x2 -

6x +

1 =

0 { 1

3 }

6. x

2 +

x +

1 −

4 =

0 {- 1

2 }

7. 25k

2 +

20

k +

4 =

0 {- 2

5 }

8. p

2 +

2p

+ 1

= 4

9

9. x

2 +

4x +

4 =

64

{-

8,

6}

{-

10,

6}

10. x

2 -

6x +

9 =

25

{-

2,

8}

11. a

2 +

8a

+ 1

6 =

1

12. 16

y2 +

8y +

1 =

0 {- 1

4 }

{-

3, -

5}

13. (x

+ 3

)2 =

49 {-

10,

4}

14. (y

+ 6

)2 =

1 {-

7, -

5}

15. (m

- 7

)2 =

49

{0

, 14}

16. (2

x +

1)2

= 1

{-

1,

0}

17. (4

x +

3)2

= 2

5 {-

2,

1 −

2 }

18. (3

h -

2)2

= 4

{ 4

3 ,

0}

19. (x

+ 1

)2 =

7

20. (y

- 3

)2 =

6

21. (m

- 2

)2 =

5

{-

1 ±

√ $

7 }

{3 ±

√ %

6 }

{2 ±

√ %

5 }

8-6

Exerc

ises

Sq

uare

Ro

ot

Pro

pert

yF

or

any n

um

ber

n >

0,

if x

2 =

n,

then x

= ± √ #

n .

Exam

ple

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-6

Ch

ap

ter

8

39

Gle

ncoe A

lgeb

ra 1

Sk

ills

Pra

ctic

e

Qu

ad

rati

c E

qu

ati

on

s:

Perf

ect

Sq

uare

s

Dete

rm

ine w

heth

er e

ach

trin

om

ial

is a

perfe

ct

sq

ua

re t

rin

om

ial.

Writ

e yes o

r no.

If s

o,

facto

r i

t.

1. m

2 -

6m

+ 9

2. r2

+ 4

r +

4

y

es;

(m -

3)2

y

es;

(r +

2)2

3. g

2 -

14g +

49

4. 2w

2 -

4w

+ 9

y

es;

(g -

7)2

n

o

5. 4

d2 -

4d

+ 1

6. 9

n2 +

30n

+ 2

5

y

es;

(2d

- 1

)2

yes;

(3n

+ 5

)2

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

, w

rit

e prim

e.

7. 2

x2 -

72

8. 6

b2 +

11b

+ 3

2

(x +

6)(

x -

6)

(2

b +

3)(

3b

+ 1

)

9. 36t2

- 2

4t +

4

10. 4

h2 -

56

4

(3t -

1)2

4

(h2 -

14)

11. 17a

2 -

24

ab

12. q

2 -

14

q +

36

a

(17a -

24

b)

pri

me

13. y

2 +

24y +

14

4

14. 6

d2 -

96

(

y +

12)2

6

(d -

4)(

d +

4)

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

15. x

2 -

18x +

81 =

0 {9}

16. 4

p2 +

4p

+ 1

= 0

{- 1

2 }

17. 9g

2 -

12g +

4 =

0 { 2

3 }

18. y

2 -

16y +

64 =

81 {-

1,

17}

19. 4n

2 -

17 =

19 {±

3}

20. x

2 +

30x +

150 =

-75 {-

15}

21. (k

+ 2

)2 =

16 {-

6,

2}

22. (m

- 4

)2 =

7 { 2

± √ %

7 }

8-6

Answers (Lesson 8-6)

Answers

Co

pyri

gh

t ©

Gle

nco

e/M

cG

raw

-Hill, a

div

isio

n o

f T

he M

cG

raw

-Hill C

om

pan

ies,

Inc.

Chapter 8 A19 Glencoe Algebra 1

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Ch

ap

ter

8

40

Gle

ncoe A

lgeb

ra 1

Practi

ce

Qu

ad

rati

c E

qu

ati

on

s:

Perf

ect

Sq

uare

s

Dete

rm

ine w

heth

er e

ach

trin

om

ial

is a

perfe

ct

sq

ua

re t

rin

om

ial.

Writ

e yes o

r no.

If s

o,

facto

r i

t.

1. m

2 +

16m

+ 6

4

2. 9r2

- 6

r +

1

3. 4

y2 -

20y +

25

y

es;

(m +

8)2

y

es;

(3r -

1)2

y

es;

(2y -

5)2

4. 16p

2 +

24

p +

9

5. 25b

2 -

4b

+ 1

6

6. 49

k2 -

56k

+ 1

6

y

es;

(4p

+ 3

)2

no

y

es;

(7k

- 4

)2

Fa

cto

r e

ach

po

lyn

om

ial,

if

po

ssib

le.

If t

he p

oly

no

mia

l ca

nn

ot

be f

acto

red

, w

rit

e

prim

e.

7. 3

p2 -

147

8. 6x

2 +

11x -

35

9. 50

q2 -

60q

+ 1

8

3

(p +

7)(

p -

7)

(2

x +

7)(

3x -

5)

2(5

q -

3)2

10. 6

t3 -

14

t2 -

12

t 11. 6d

2 -

18

12. 30

k2 +

38k

+ 1

2

2

t(3t +

2)(

t -

3)

6(d

2 -

3)

2(5

k +

3)(

3k

+ 2

)

13. 15b

2 -

24

bf

14. 12h

2 -

60

h +

75

15. 9

n2 -

30

n -

25

3

b(5

b -

8f)

3

(2h

- 5

)2

pri

me

16. 7

u2 -

28m

2

17. w

4 -

8w

2 -

9

18. 16a

2 +

72a

d +

81d

2

7

(u -

2m

)(u

+ 2

m)

(w

2 +

1)(

w +

3)(

w -

3)

(4

a +

9d

)2

So

lve e

ach

eq

ua

tio

n.

Ch

eck

th

e s

olu

tio

ns.

19. 4

k2 -

28k

= -

49

20. 50b

2 +

20

b +

2 =

0

21. ( 1

2 t

- 1

) 2

= 0

{ 7

2 }

{- 1

5 }

{2}

22. g

2 +

2

3 g

+ 1

9 =

0

23. p

2 -

6

5 p

+

9

25 =

0

24. x

2 +

12

x +

36 =

25

{-

1 −

3 }

{ 3 −

5 }

{-

11, -

1}

25. y

2 -

8y +

16 =

64

26. (h

+ 9

)2 =

3

27. w

2 -

6w

+ 9

= 1

3

{-

4,

12}

{-

9 ±

√ $

3 }

{3 ±

√ $$

13 }

28. G

EO

METR

Y T

he a

rea o

f a c

ircl

e i

s giv

en

by t

he f

orm

ula

A =

πr2

, w

here

r i

s th

e r

ad

ius.

If

in

creasi

ng t

he r

ad

ius

of

a c

ircl

e b

y 1

in

ch g

ives

the r

esu

ltin

g c

ircl

e a

n a

rea o

f 100

π

squ

are

in

ches,

wh

at

is t

he r

ad

ius

of

the o

rigin

al

circ

le?

9 i

n.

29. PIC

TU

RE F

RA

MIN

G M

ikaela

pla

ced

a f

ram

e a

rou

nd

a p

rin

t th

at

m

easu

res

10 i

nch

es

by 1

0 i

nch

es.

Th

e a

rea o

f ju

st t

he f

ram

e i

tself

is

69 s

qu

are

in

ches.

Wh

at

is t

he w

idth

of

the f

ram

e?

1.5

in

.1

0

10

x

x

8-6

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

NA

ME

DA

TE

PE

RIO

D

Lesson 8-6

Ch

ap

ter

8

41

Gle

ncoe A

lgeb

ra 1

Wo

rd

Pro

ble

m P

racti

ce

Qu

ad

rati

c E

qu

ati

on

s:

Perf

ect

Sq

uare

s

1. C

ON

STR

UC

TIO

N T

he a

rea o

f L

ibert

y

Tow

nsh

ip’s

squ

are

pla

ygro

un

d i

s re

pre

sen

ted

by t

he t

rin

om

ial

x2

- 1

0x

+ 2

5.

Wri

te a

n e

xp

ress

ion

u

sin

g t

he v

ari

able

x t

hat

rep

rese

nts

th

e

peri

mete

r. 4

x-

20 o

r 4(x-

5)

2. A

MU

SEM

EN

T P

AR

KS

F

un

tow

n

Dow

nto

wn

wan

ts t

o b

uil

d a

vert

ical

moti

on

rid

e w

here

th

e p

ass

en

gers

are

la

un

ched

str

aig

ht

up

ward

fro

m g

rou

nd

le

vel

wit

h a

n i

nit

ial

velo

city

of

96 f

eet

per

seco

nd

. T

he r

ide c

ar’

s h

eig

ht

h i

n f

eet

aft

er

t se

con

ds

is h

= 9

6t

- 1

6t2

. H

ow

m

an

y s

eco

nd

s aft

er

lau

nch

wou

ld t

he c

ar

reach

144 f

eet?

3 s

eco

nd

s

3. B

USIN

ESS

S

ain

i S

pri

nk

ler

Com

pan

y

inst

all

s ir

rigati

on

syst

em

s. T

o t

rack

m

on

thly

cost

s C

an

d r

even

ues

R,

they

use

th

e f

oll

ow

ing f

un

ctio

ns,

wh

ere

x i

s th

e n

um

ber

of

syst

em

s th

ey i

nst

all

.

R

(x)

= 8

x2 +

12x

+ 4

C(x

) =

7x

2 +

20x

- 1

2

Th

e m

on

thly

pro

fit

can

be f

ou

nd

by

subtr

act

ing c

ost

fro

m r

even

ue.

P(x

) =

R(x

) -

C(x

)

Fin

d a

fu

nct

ion

to p

roje

ct m

on

thly

pro

fit

an

d u

se i

t to

fin

d t

he b

reak

-even

poin

t w

here

th

e p

rofi

t is

zero

.

P(x

) =

x2-

8x+

16;

x=

4

4. G

EO

METR

YH

oll

y c

an

mak

e a

n o

pen

-to

pp

ed

box o

ut

of

a s

qu

are

pie

ce o

f ca

rdboard

by c

utt

ing 3

-in

ch s

qu

are

s fr

om

th

e c

orn

ers

an

d f

old

ing u

p t

he s

ides

to

meet.

Th

e v

olu

me o

f th

e r

esu

ltin

g b

ox i

s V

=3

x2

-36x

+108,

wh

ere

x i

s th

e

ori

gin

al

len

gth

an

d w

idth

of

the

card

board

.

a.

Fact

or

the p

oly

nom

ial

exp

ress

ion

fro

m

the v

olu

me e

qu

ati

on

. 3(x-

6)(

x-

6)

b

. W

hat

is t

he v

olu

me o

f th

e b

ox i

f th

e

ori

gin

al

len

gth

of

each

sid

e o

f th

e

card

board

was

14 i

nch

es?

192 i

n3

c.

Wh

at

is t

he o

rigin

al

sid

e l

en

gth

of

the

card

board

wh

en

th

e v

olu

me o

f th

e b

ox

is 2

7 i

n3?

9 i

n.

x

x

3 in

3 in

8-6

Answers (Lesson 8-6)

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