x平方-2xy+y平方-1/x-y-1,化简!
问题描述：
x平方-2xy+y平方-1/x-y-1,化简!
答
(x^2-2xy+y^2-1)/(x-y-1)
=[(x-y)^2-1]/(x-y-1)
=(x-y-1)(x-y+1)/(x-y-1)
=x-y+1