A paper company needs to ship paper to a large printing business. The paper will be shipped in small boxes and large boxes. The volume of each small box is 9 cubic feet and the volume of each large box is 12 cubic feet. A total of 20 boxes of paper were shipped with a combined volume of 216 cubic feet. Graphically solve a system of equations in order to determine the number of small boxes shipped, x,x, and the number of large boxes shipped, yy.