A graph is shown below: A graph is shown. The values on the x axis are 0, 4, 8, 12, 16, and 20. The values on the y axis are 0, 16, 32, 48, 64, and 80. Points are shown on ordered pairs 0, 64 and 4, 48 and 8, 32 and 12, 16 and 16, 0. These points are connected by a line.

What is the equation of the line in slope-intercept form?