6x+5y=120, 7x+11y=202 solve for x and y
6x=120-5y -> x=20-5/6y -> 7(20-5/6y) + 11y =202 -> 140-35/6y + 11y = 202 -> 140+31/6y=202 -> 31/6*y = 62 -> y = 12.