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