8.2 Chapter 8

Writing equations from 2 points

100

(0, -1), (1,4)

y = 5x - 1

200

(1,0), (2,4)

y = 4x - 4

300

(-4,-4), (1,6)

y = 2x + 4

400

(-8,9), (-2,-9)

y = -3x - 15

500

(-3, 8), (2, -2)

y = -2x + 2

writing equations from x/y intercepts

100

x intercept 0, y intercept 0

y = x

200

x intercept 7, y intercept 0

y = x + 7

300

x intercept 3, y intercept 6

y= -2x + 6

400

y intercept -4 and the line is parallel to y = 3x 

y = 3x - 4

500

Slope 1/2, x intercept 4

y = 1/2x -2

finding the slope from an equation

100

y = -x + 7

-1

200

2x + 2y = 2

m = -1

300

6x + 2y = 7

m = -3

400

x + 7y = -20

m = -1/7

500

20x + 2y = –9

x = -10

write equations from a slope and a point

100

slope 1 point (0,1)

y = x + 1

200

slope 1 point (1,0)

y = x - 1

300

A line has a slope of –7 and passes through the point 

(2,7)

y = -7x + 21

400

A line has a slope of 7 and passes through the point 

(-1, -8)

y = 7x - 1

500

A line has a slope of 1/2 and passes through the point 

(4,6)

y = 1/2x + 4

writing equations from a slop and x/y intercept

100

slope of -9 and y-intercept of 6

y = -9x + 6

200

slope of 1, y intercept 0

y = x

300

Slope -⅓ , x intercept 3

y = -1/3x +1

400

slope 0 y intercept 7

y = 7

500

Slope -5 , x intercept 3

y = -5x +15