Question

How do you find the slope of a line perpendicular to a given line?

Answer 1

you have a line:
y=mx+b  (slope-intercepted form)
m=slope of this line.

The slope of a line perpendicular to that given line will be: ´"m´"
m´=-1/m.

For example:
y=8x+3
m=8

The solpe fo a line perpendicular to "y=8x+3" is:
m`=-1/8