Find an equation for the line perpendicular

Question

Find an equation for the line perpendicular to y = − 1/ 5 x + 2 and goes through the point ( − 5 , − 8 ) . Write your answer in the form y = m x + b .

Answer 1

We can do this two ways. Remember that perpendicular lines hsve oppisite, reciprocal slopes.

1. Use point-slope form.

y - (-8) = 5(x - (-5))

y + 8 = 5x + 25

y = 5x + 17

2. Solve for b.

-8 = 5(-5) + b

-8 = -25 + b

b = 17

y = 5x + 17