计算 （xy分之X的平方-Y的平方）平方 * （x-y分之x）的立方
问题描述：
计算 （xy分之X的平方-Y的平方）平方 * （x-y分之x）的立方
答
[(x^2-y^2)/xy]^2*[x/(x-y)]^3
=[(x^2-y^2)/xy*x/(x-y)]^2*x/(x-y)
=[(x^2-y^2)/y*1/(x-y)]^2*x/(x-y)
=[(x-y)(x+y)/y*1/(x-y)]^2*x/(x-y)
=[(x+y)/y*]^2*x/(x-y)
=(x+y)^2/y^2*x/(x-y)
=x(x+y)^2/[y^2(x-y)]