Question

Write an equation in slope-intercept form for the line that satisfies the following condition.

passes through (18, –9), perpendicular to the graph of y = x + 25

Answer 1

y = - x + 9

Explanation:

the equation of a line in slope- intercept form is

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

given the equation

y = x + 25 ← in slope- intercept form

with slope m = 1

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

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

y = - x + c ← is the partial equation

to find c , substitute (18, - 9 ) into the partial equation

- 9 = - 18 + c ( add 18 to both sides )

9 = c

y = - x + 9 ← equation of perpendicular line