5a(x+y) - x - y = 5ax + 5ay - x - y5a(x+y) - x - y = x(5a - 1) + y(5a - 1)5a(x+y) - x - y = (5a - 1)(x + y)
5a(x+y) - x - y = 5ax + 5ay - x - y
5a(x+y) - x - y = x(5a - 1) + y(5a - 1)
5a(x+y) - x - y = (5a - 1)(x + y)