问题
解答题
先化简，再求值：
|
答案
+x2-x x2-1
-x+1 x2-1 x3-2x+1 x2-1
=-x3+x2+2x x2-1
=-x(x2-x-2) (x-1)(x+1)
=-x(x+1)(x-2) (x-1)(x+1)
=-
，x(x-2) x-1
当x=-2时，原式=
．8 3
搜题请搜索小程序“爱下问搜题”
先化简，再求值：
|
+x2-x x2-1
-x+1 x2-1 x3-2x+1 x2-1
=-x3+x2+2x x2-1
=-x(x2-x-2) (x-1)(x+1)
=-x(x+1)(x-2) (x-1)(x+1)
=-
，x(x-2) x-1
当x=-2时，原式=
．8 3