问题
解答题
先化简,再求值:(
|
答案
(
-x2-4 x2-4x+4
)÷x-2 x+2
,x x-2
=(
-(x+2)(x-2) (x-2)2
)×x-2 x+2
,x-2 x
=(
-x+2 x-2
)×x-2 x+2
,x-2 x
=
×x2+4x+4-x2+4x-4 (x-2)(x+2)
,x-2 x
=
×8x (x-2)(x+2)
,x-2 x
=
,8 x+2
当x=2
-2时,原式=3
=8 2
-2+23
.4 3 3