Question

Line A passes through the point (−8, 3) and is perpendicular to the line represented by the equation y=−4x+9 . What is the slope, m , and y-intercept, b , of line A? Enter your answers in the boxes.

Answer 1

m =
`(1)/(4)` , b = 5

Explanation:

the equation of a line in slope- intercept form is

y = mx + b ( m is the slope and b the y- intercept )

y = - 4x + 9 ← is in slope- intercept form

with slope m = - 4

given a line with slope m then the slope of a line perpendicular to it is

`m_(perpendicular)` = -
`(1)/(m)` = -
`(1)/(-4)` =
`(1)/(4)` , then

y =
`(1)/(4)` x + b ← is the partial equation of line A

to find b substitute (- 8, 3 ) into the partial equation

3 =
`(1)/(4)` (- 8) + b = - 2 + b ( add 2 to both sides )

5 = b

for line A , slope m =
`(1)/(4)` and y- intercept b = 5