Question

Find an equation of the line L that passes through the point (2,-12) and satisfies the given condition.

L is perpendicular to the line 8x + 2y = -8.

Answer 1

y = 1/4 x - 12.5

Explanation:

8x + 2y = -8 (rewrite in y = mx + b form)

2y = -8x -8 (divide both sides by 2)

y = -4x -2 for first line

Perpendicular line L has "opposite/inverse" slope

y = -4x + b becomes y = 1/4 x + b

What's b (the y-intercept)?

Plug the point (2, -12) into the equation y = 1/4 x + b to solve for b

-12 = 1/4 (2) + b

-12 = 1/2 + b (subtract 1/2 from both sides)

-12.5 =b (rewrite equation)

y = 1/4 x - 12.5