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(x的平方-xy分之y+y的平方-xy分之X)乘x-y分之xy

题目详情
(x的平方-xy分之y+y的平方-xy分之X)乘x-y分之xy
▼优质解答
答案和解析
(x的平方-xy分之y+y的平方-xy分之X)乘x-y分之xy
=[y/x(x-y)-x/y(x-y)]*[xy/(x-y)]
=[(y²-x²)/xy(x-y)]*xy/(x-y)
=-(x-y)(x+y)/(x-y)²
=-(x+y)/(x-y)