Quote (Azrad @ Jan 22 2014 10:21am)
kind of, heh. This problem is kind of a gotcha. The slope of the line x = 1 is undefined. (change in y)/(change in x), and in this case x does not change, so the slope calculation has a divide by zero problem.
equation is actually not y = a*x + b but a*x + b*y + c = 0 (particularly because of what you said)