问题 解答题
(1)已知x=
2
+1
,求(1-
1
x
)
÷
x2-2x+1
x
的值.
(2)计算:2
2
2
+
1
2
)-
27
-
12
3
答案

(1)原式=

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

当x=

2
+1时,原式=
1
2
=
2
2

(2)原式=4+2-(3-2)

=6-1

=5.

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