Quote Originally Posted by a500lbgorilla View Post
A horizontal line would be y = 5. m = 0.

A vertical line would be x = 5. m has no meaning.
This makes no sense to me. I understand why m = 0 on a horizontal line and why it has no meaning on a vertical line. But why are y and x 5? Or is that just an arbitrary number you pulled out of your butt?