化简(x2-1x2-2x+1+1-x/x+1)÷x/x-1的结果是_．
问题描述：
化简(
+
x2-1
x2-2x+1
)÷1-x x+1
的结果是______． x x-1
答
原式=[
-(x+1)(x-1) (x-1)2
]•x-1 x+1
x-1 x
=
-x+1 x
(x-1)2
x(x+1)
=
(x+1)2-(x-1)2
x(x+1)
=
4x x(x+1)
=
．4 x+1
故答案为：
．4 x+1