5.1 Algebraic Expressions

CAN YOU FOLLOW ORDER OF OPERATIONS?

PEMDAS

• Please

• Excuse

• My Dear

• Aunt Sally

Can You . . .

Evaluate an algebraic expression?

Let’s try it . . .

To evaluate an algebraic expression:

FIRST, substitute a given number(s) for

the variable(s)

FINALLY, find the value of the resulting

numerical expression (Use Order of

Operations!!)

Evaluate each expression for the given value of the variable. You will have to use Order of Operations!

Substitute 15 for x.

Subtract.

1. x – 9 for x = 15

15 – 9

6

Substitute 3 for y.

Multiply.

2. 5y + 7 for y = 3 5(3) + 7 15 + 7

Add.22

Evaluate each expression for the given value of the variable. Show one step at a time!

Substitute 2 for e.

Multiply.

3. 9e for e = 2

9(2)18

Substitute 5 for t

Multiply.

4. 6t - 24 for t = 5

6(5) - 24

30 - 24 Subtract.6

Evaluate the expression for the given values of the variable.

6(x + 6) + 4 for x = 5, 6, 7

5

6

7

x Substitute Parentheses Multiply Add

6(5 + 6) + 4 6(11) + 4 66 + 4 70

6(6 + 6) + 4 6(12) + 4 72 + 4 76

6(7 + 6) + 4 6(13) + 4 78 + 4 82

Evaluate the expression for the given values of the variable.

5(n - 8) – 2 for n = 10, 15, 20

10

15

20

n Substitute Parentheses Multiply Subtract

5(10 - 8) - 2 5(2) – 2 10 – 2 8

5(15 - 8) - 2 5(7) – 2 35 – 2 33

5(20 - 8) - 2 5(12) – 2 60 – 2 58

Evaluate each expression for the given value of the variables.

Substitute 2 for x and 1 for y.

Multiply.

11. 4x + 3y for x = 2 and y = 1

4(2) + 3(1)

8 + 3

Substitute 12 for m and 8 for n.

Multiply.

12. 3m – 4.1n for m = 12 and n = 8

3(12) – 4.1(8)

36 – 32.8

Add.11

Subtract.3.2

Evaluate each expression for the given value of the variables.

Substitute 3 for x and 4 for y.

Multiply.

13. xy – 4 • 2 for x = 3 and y = 4

3(4) – 4 • 2

12 - 8

Substitute 5 for x and 12 for y.

Divide.

14. 60 – y for x = 5 and y = 12 x

60 – 12 5

12 – 12

Subtract.4

Subtract.0

Can You . . .

Evaluate an algebraic expression?

Warm UpShow your work One Step at a Time!

Write an algebraic expression for the following phrases.

4. 47 more than the product of 81 and a number n

5. Divide the difference of 31 and a number c by 54

6. The product of x and 5 decreased by 23

1. (1 + 2 • 3)2 ÷ 7

2. 2(3 +1) - 7

3. (16 – 5 • 3)2 + 9