make a graph and put a point at exactly (1,2) and then make a like at y=3 make a line through the point and you'll see that this is an undefined equation x cant equal all those numbers
As the line is perpendicular to y = 3 it well be of the form x = some number. And the point (1,2) has an x-coordinate of 1 so the line passes through x = 1.
