[-3(x-y)^3]^2•（y-x)^3
问题描述：
[-3(x-y)^3]^2•（y-x)^3
答
[-3(x-y)^3]^2•（y-x)^3
=[9(x-y)^6]*[-(x-y)^3]
=-9(x-y)^9