How to determine if an equation defines y as a function of x

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line

The coordinates of a, b, and c in the diagram are a(p,4), b(6,1), and c(9,q). which equation correctly relates p and q? hint: since is perpendicular to , the slope of × the slope of = -1. a. p - q = 7 b. q - p = 7 c. -q - p = 7 d. p + q = 7

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?