What is the equation of the line that passes through the point (−6,6) and has an undefined slope?

Answer 1

The point we are given is (x1, y1) = (-6,6) and m is undefined. I assume that undefined here does not mean unknown, but that it has an infinite slope, i.e. the line points either straight up or straight down. That means it's a vertical line, which has the form x = x1.

So the line equation is x = -6.