化简-x∧3-xy∧2+ 2x∧2y/x∧3-y∧2x
问题描述：
化简-x∧3-xy∧2+ 2x∧2y/x∧3-y∧2x
答
(-x^3-xy^2+2x^2y) / (x^3-y^2x)
=-x(x^2+y^2-2xy) / [-x(x^2-y^2)]
= (x-y)^2 / [(x+y)(x-y)]
= (x-y) / (x+y)