原式=[x(2x^2-2xy^2+2xy^2-x^2)]/(x^2y)
=x^3/(x^2y)
=x/y详细点可以不不好意思，我发现刚刚看错了题应该是：原式=[x(2x^2-2xy^2+2xy^2-x^2y)]/(x^2y) =[x(2x^2-x^2y)]/(x^2y) =[x^3(2-y)]/(x^2y) =x(2-y)/y