Draw the graph of the linear equation with y-intercept 2 and no x-intercept. Clearly, the x-axis would have a higher quarterback rating in this scenario. There we go, back to the football.
First we draw the intercept:
For a line to go through this point and never hit the x-axis, the line must be horizontal, and therefore parallel to the x-axis. Remember how parallel lines never touch each other? It's not just because they are intense germophobes either.