1) 2a + a(b + c) = a(2 + b + c)
2) x(y + z) + 3x = x(y + z + 3)
3) 2a - a(b - c) = a(2 - b + c)
4) 3x - x(y - z) = x(3 - y + z)
5) 2(a + b) - c(a + b) = (2 - c)(a + b)
6) 3(x + y) - z(x + y) = (3 - z)(x + y)
