问题 解答题
计算或化简:
(1)
8
-
2
(
2
+2)

(2)
2
3
-1
+
27
-(
3
-1)0+(-2)-2-3
1
3

(3)(6
x
4
-2x
1
x
)÷3
x

(4)已知:x=
2
3
-1
,求x2-x+1的值.
答案

(1)

8
-
2
(
2
+2),

=2

2
-2-2
2

=-2;

(2)

2
3
-1
+
27
-(
3
-1)0+(-2)-2-3
1
3

=

3
+1+3
3
-1+
1
4
-
3

=3

3
+
1
4

(3)(6

x
4
-2x
1
x
)÷3
x

=(3

x
-2
x
÷3
x

=

1
3

(4)∵x=

2
3
-1
=
3
+1

∴x2-x+1,

=(

3
+1)2-(
3
+1
)+1,

=4+2

3
-
3
-1+1,

=4+

3

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