A school is organizing a cookout where hotdogs will be served. The hotdogs come in small packs and large packs. Each small pack has 12 hotdogs and each large pack has 24 hotdogs. The school bought 4 times as many small packs as large packs, which altogether had 144 hotdogs. Graphically solve a system of equations in order to determine the number of small packs purchased, x, x, and the number of large packs purchased, yy.