The screen is a coordinate plane that goes from (-240, -180) in the bottom left to (240, 180) in the top right.
For some reason if you enter a fraction as the slope or y intercept counts it as 0. but with decimals it's fine. Realized that if the y is above 180 or below -180 it displays weird, so I made it not draw it if it's above 180 or below -180
