问题 填空题
化简后
3-2
2
+
5-2
6
+
7-2
12
+
9-2
20
+
11-2
30
+
13-2
42
+
15-2
56
+
17-2
72
=
______.
答案

3-2
2
+
5-2
6
+
7-2
12
+
9-2
20
+
11-2
30
+
13-2
42
+
15-2
56
+
17-2
72
=

=

2
-1+
3
-
2
+
4
-
3
+
5
-
4
+
6
-
5
+
7
-
6
+
8
-
7
+
9
-
8

=3-1

=2.

故答案为:2.

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