2 (X-Y) square - 7 (X-Y) cube + 3 (Y-X) square + (Y-X) cube. How to simplify?

2 (X-Y) square - 7 (X-Y) cube + 3 (Y-X) square + (Y-X) cube. How to simplify?

Square of 2 (X-Y) - cube of 7 (X-Y) + square of 3 (Y-X) + (Y-X)
=2(x-y)^2-7(x-y)^3+3(x-y)^2-(x-y)^3
=5(x-y)^2-8(x-y)^3