问题
解答题
(1)计算:(-
(2)先化简,再求值:已知x=
|
答案
(1)原式=1-3-
+2×3 3 2
=1-3-
+3 3
=-2;
(2)原式=[
-x+1 x(x-1)
]•xx (x-1)2
=
•xx2-1-x2 x(x-1)2
=-
,1 (x-1)2
当x=
+1时,原式=-2
=-1 (
+1-1)22
.1 2
(1)计算:(-
(2)先化简,再求值:已知x=
|
(1)原式=1-3-
+2×3 3 2
=1-3-
+3 3
=-2;
(2)原式=[
-x+1 x(x-1)
]•xx (x-1)2
=
•xx2-1-x2 x(x-1)2
=-
,1 (x-1)2
当x=
+1时,原式=-2
=-1 (
+1-1)22
.1 2