分解因式 x(x-y)^5+xy(y-x)^4-x^3(x-y)3

=x(x-y)^3[(x-y)^2+y(x-y)-x^2]
=x(x-y)^3[(x-y)(x-y+y)-x^2]
=x(x-y)^3[(x-y)*x-x^2]
=x^2*(x-y)^3[(x-y)-x]
=-x^2*y*(x-y)^3谢谢，还有最后一道 -16(a+b)^4+81(a-b)^4