问题
解答题
计算:(1)
(2)先化简,再求值:
|
答案
(1)原式=2-1+2=3;
(2)原式=
-x+1 (x+1)(x-1)
=2 (x+1)(x-1)
=x-1 (x+1)(x-1)
,1 x+1
当x=-2时,原式=
=-1.1 -2+1
计算:(1)
(2)先化简,再求值:
|
(1)原式=2-1+2=3;
(2)原式=
-x+1 (x+1)(x-1)
=2 (x+1)(x-1)
=x-1 (x+1)(x-1)
,1 x+1
当x=-2时,原式=
=-1.1 -2+1