7x - 3y = 20 July 8, 2019 16 32 64 128 7x 3y 20 y 5x 4 7x 3y 20 5x 2y 14 Begin aligned & 7x-3y = 20 and y=5x-4 end aligned 7x 2 20xy 3y 2 7x 3y 20 5x 2y 14 indicar x y