计算:(x^2-2x+1-y^2)/(x+y-1)RT

问题描述:

计算:(x^2-2x+1-y^2)/(x+y-1)
RT

(x^2-2x+1-y^2)/(x+y-1)
=[(x-1)^2-y^2]/(x+y-1)
=(x+y-1)(x-y-1)/(x+y-1)
=x-y-1