What is the factor of these expressions?

Question

1.) ax-by+ay-bx
2.) x^18 - y^6
3.) 6x^2 + 53x +40
4.) x^2 - 16x + 63

Answer 1

1) (a - b)(x - y)
2) (x^9 + y^3)(x^9 - y^3)
3) (6x + 5)(x + 8)
4) (x - 9)(x - 7)