问题 解答题
计算:
(1)
12
+
20
-(
5
-
3
)
                
(2)(
9a
+a
1
a
-
2
a
a3
b

(3)
1+(2+
3
)2
(
7
-
3
)(
7
+
3
)
              
(4)
12
+|-
3
|-(-2006)0+(
1
2
)-1
答案

(1)原式=2

3
+2
5
-
5
+
3

=3

3
+
5

(2)原式=(3

a
+
a
-2
a
)÷
b

=2

a
÷
b

=

2
ab
b

(3)原式=

1+4+4
3
+3
7-3

=

8+4
3
4

=2+

3

(4)原式=2

3
+
3
-1+2

=3

3
+1.

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