Question

What is the slope of a line that is perpendicular to the line whose equation is ax+by=c?

A. c/b
B. b/a
C. −b/a
D. a/b

Answer 1

b/a

Explanation:

ax+by=c

To find the slope solve for y

by = -ax+c

Divide by b

y = -a/b x + c/b

The slope intercept form is y = mx+b where m is the slope

The slope is -a/b

A perpendicular line has a slope that is the negative reciprocal

-1/ (-a/b)

-1 * -b/a

b/a