问题 解答题
(1)计算:-32-(-
1
2
)-3-|1-
3
|+
27

(2)先化简,再求值:(
1
x2-2x
-
1
x2-4x+4
)÷
2
x2-2x
,其中x=1.
答案

(1)原式=-9-(-8)+1-

3
+3
3

=2

3

(2)原式=[

1
x(x-2)
-
1
(x-2)2
x(x-2)
2

=

1
x(x-2)
×
x(x-2)
2
-
1
(x-2)2
×
x(x-2)
2

=

1
2
-
x
2(x-2)

=

x-2-x
2(x-2)
=
1
2-x

当x=1时,原式=

1
2-1
=1.

单项选择题
单项选择题