计算：(x-y)^2/(x+y)÷(y-x)×1/(x-y)
问题描述：
计算：(x-y)^2/(x+y)÷(y-x)×1/(x-y)
(m^2-4n^2)/(3mn^3)×mn/(m+2n)
答
原式=(x-y)^2/(x+y)×[-1/(x-y)]×1/(x-y)
=-(x-y)/(x+y)×1/(x-y)
=-1/(x+y)
原式=(m+2n)(m-2n)/(3mn^3)×mn/(m+2n)
=(m-2n)/(3n^2