2(X-Y)的平方-7(X-Y)的立方+3(y-x)的平方+(y-x)的立方.怎麼化簡?

2(X-Y)的平方-7(X-Y)的立方+3(y-x)的平方+(y-x)的立方.怎麼化簡?

2(X-Y)的平方-7(X-Y)的立方+3(y-x)的平方+(y-x)的立方
=2(x-y)^2-7(x-y)^3+3(x-y)^2-(x-y)^3
=5(x-y)^2-8(x-y)^3