閱讀并按要求完成各題．
（1）在化簡
7
-2
10
的過程中，小王和小李的化簡結果不一樣：
小王的化簡過程如下：
原式=
2-2
2×5
+5
=
(
2
)2-2
2
•
5
+(
5
)2
=
(
2
-
5
)2
=
2
-
5
．
小李的化簡過程如下：
原式=
(
2
)2-2
2
•
5
+(
5
)2
=
(
2
-
5
)2
=
5
-
2
．
請判斷誰的化簡結果正確，并說明理由．
（2）已知x=
6-2
5
，求(
1
x-2
+
1
x+2
)•
x2-4
2(x-1)
的值．（結果保留根號）
分析：（1）根據(jù)二次根式的性質得到
(
2
-
5)2
=|
2
-
5
|=
5
-
2
，由此可判斷小李的化簡結果正確．
（2）理由（1）的方法可化簡x得到x=
5
-1，再對分式進行通分、約分得到原式=
x
x-1
，然后把x的值代入后解分母有理化即可．
解答：解：（1）小李的化簡結果正確．理由如下：
(
2
-
5)2
=|
2
-
5
|=
5
-
2
；
（2）x=
5-2
5
+1
=
(
5)2-2
5
+1
=
(
5
-1)2
=
5
-1，
原式=
x+2+x-2
(x-2)(x+2)
•
(x+2)(x-2)
2(x-1)

=
x
x-1
，
當x=
5
-1時，原式=
5
-1
5
-1-1
=3+
5
．
點評：本題考查了二次根式的化簡求值：先化簡再代入求值；二次根式運算的最后，注意結果要化到最簡二次根式，二次根式的乘除運算要與加減運算區(qū)分，避免互相干擾．也考查了分式的化簡求值．
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