Post on 18-Jan-2018
description
7.2 Two-Variable Linear Systems
Elimination method
Solve for (x, y)
Given the System, I want to reduce the number of variables. By multiplying both sides of each equation by a number, we can have opposite coefficients to add together to eliminate a variable.
50562023
yxyx
Solve for (x, y)
Given 5056505615056
4046 202322023
yxyxyxyxyxyx
10
10
y
y
Solve for (x, y)
Given 5056505615056
4046 202322023
yxyxyxyxyxyx
10
10
y
y
Now to find x replace y with 10, in either equation
Solve for (x, y)
Given 5056505615056
4046 202322023
yxyxyxyxyxyx
10 10
yy
003
20203201023
xxxx
10,0
Airplane SpeedAn airplane flying into a headwind travels
the 1800-mile flying distance between Pittsburgh, Pennsylvania and Phoenix, Arizona in 3 hour hours and 36 minutes. On the return flight, the distance is traveled in 3 hours. Find the airspeed of the plane and the speed of the wind, assuming that both remain constant.
Airplane SpeedAirplane travels the 1800-mile in 3 hour
hours and 36 minutes. Return the same distance in 3 hours.
Find the airspeed, speed of the wind, both constant. Write variable for Speeds
Airplane speed r
Wind speed w
Airplane SpeedAirplane travels the 1800-mile in 3 hour
hours and 36 minutes. Return the same distance in 3 hours.
Airplane speed r
Wind speed w
1800)3(
180060363
wr
wr
Airplane Speed
1800)3(
180060363
wr
wr
3
18001800)3(
6.3180018006.3
wrwr
wrwr
Airplane Speed
1800)3(
180060363
wr
wr
600 1800)3(
50018006.3
wrwrwrwr
550 11002
rr
Airplane Speed 600
500
wrwr
550 11002
rr
50 600550
ww
Homework
Page 495 -498 # 4, 16, 24, 32,
40, 48, 49, 63, 74, 80
Homework
Page 495 -498 # 12, 20, 28, 36, 44, 52, 67, 76, 82