The equation for slope-intercept form is y=mx + b, where m is the slope and b is the y-intercept. To find the slope, you find the change in Y over the change in X. In this case, w, you have two constant points on the line which give us the slope 5/4. Then using the rest of the line can calculate the y-intercept. Since the last point the line is on is 15, you need to change the change in y to 1. Therefore, you add 1 and 1/4 to 15, giving you the answer 16 1/4.
