问题 解答题
(1)计算:
2
2
(2
12
+4
1
8
-3
48
)

(2)分解因式:(x2-2x)2+2(x2-2x)+1
(3)先化简,再求值:
x-1
x
÷(x-
2x-1
x
)
,其中x=
5
+1.
答案

(1)原式=

2
2
×2
12
+
2
2
×4
1
8
-
2
2
×3
48

=2

6
+2×
1
2
-
3
2
×4
6

=2

6
+1-6
6

=-1-4

6

(2)原式=(x2-2x+1)2

=[(x-1)2]2

=(x-1)4

(3)

x-1
x
÷(x-
2x-1
x

=

x-1
x
÷
x2-2x+1
x

=

x-1
x
x
(x-1)2

=

1
x-1

当x=

5
+1时,原式=
1
5
+1-1
=
5
5

单项选择题
单项选择题