化简:x2−2xy+y2−1x−y−1=_.
问题描述:
化简:
=______.
x2−2xy+y2−1 x−y−1
答
原式=
=
(x−y)2−1 x−y−1
=x-y+1.(x−y+1)(x−y−1) x−y−1