John is a songwriter who collects royalties on his songs whenever they are played in a commercial or a movie. John will earn $20 every time one of his songs is played in a commercial and he will earn $80 every time one of his songs is played in a movie. John's songs were played on 4 times as many commercials as movies and his total earnings on the royalties from all commercials and movies was $320. Graphically solve a system of equations in order to determine the number of commercials, x, and the number of movies,y, on which John's songs were played.