Question

Write an equation of the line with the given characteristics (show all work)

1. points on line: (-1,9), (1,1)

2. Vertical line through (-8,6)

Answer 1

1. y = - 4 x + 5

2. x = -8

Explanation:

1. (-1,9) (1,1)

y = mx + b

m = (y-y') / (x-x') = (1-9) / (1-(-1)) = -8 / 2 = - 4

b = y - mx = 9 - (-4) x (-1) = 5

equation: y = - 4 x + 5

check: (1,1) y=1 = (-4) x 1 + 5 = 1

2. Vertical line through (-8,6) is a line perpendicular to x axis

x = -8