
Curtis H. answered 05/06/20
Supportive and Effective Tutor Specializing in Math + All Test Prep
X=-2
X=c where c is any constant will describe a vertical line through all points that have an x value of c. Or another way to look at it is the set of all points (c,y) is a vertical line. If you know you're dealing with a vertical line the you only need one point to determine the formula (same with horizontal lines but they are defines as Y=c where c is any constant).