计算 x\x+y-2xy/y^2-x^2

问题描述:

计算 x\x+y-2xy/y^2-x^2

x\x+y-2xy/y^2-x^2
=x\x+y+2xy/(x+y)(x-y)
=【x²-xy+2xy】/(x+y)(x-y)
=(x²+xy)/(x+y)(x-y)
=x/(x-y)