to graph a LINEar equation, since it's just a straight line, recall, to draw a straight line all you need is two points.
so we can just pick two random "x" values, hmmmmm say x = 0, what's "y"?
y = 7(0)-7 => y = -7....................................... so that gives us the point (0, -7)
hmmm x = 2, what is "y"?
y = 7(2) - 7 => y = 14-7 => y = 7................. so we get the point (2, 7).
then just plot those, and run a line through them.