问题
解答题
(1)计算:
(2)先化简,再求值:
|
答案
(1)
-1 12
+(2-(1-
)23
)0+(-5
)-11 2
=
-(3 6
-1)+1-23
=
-3 6
+1+1-23
=-
;5 3 6
(2)
÷(x-1-x2-2x x2-1
)2x-1 x+1
=
÷x(x-2) (x+1)(x-1) x2-1-2x+1 x+1
=
×x(x-2) (x+1)(x-1) x+1 x(x-2)
=
,1 x-1
当x=
+1时,原式=2
=1 x-1
=1
+1-12
.2 2