问题
解答题
先化简,后求值:(1+
|
答案
(1+
)÷1 x-2 x2-2x+1 x2-4
=
÷x-2+1 x-2
(3分)(x-1)2 (x+2)(x-2)
=
×x-1 x-2
(4分)(x+2)(x-2) (x-1)2
=
,(5分)x+2 x-1
当x=-5时,原式=
=x+2 x-1
=-5+2 -5-1
.(7分)1 2
先化简,后求值:(1+
|
(1+
)÷1 x-2 x2-2x+1 x2-4
=
÷x-2+1 x-2
(3分)(x-1)2 (x+2)(x-2)
=
×x-1 x-2
(4分)(x+2)(x-2) (x-1)2
=
,(5分)x+2 x-1
当x=-5时,原式=
=x+2 x-1
=-5+2 -5-1
.(7分)1 2