问题
解答题
|
答案
原式=
+
-12 (1+ 2)(
-1)2
+…+
- 3 2 (
+3
)(2
-3
)2
+
-8 7 (
+8
)(7
- 8
)7
-9 8 (
+8
)(9
-9
) 8
=
-1+2
-3
+2
-4
+…+3
-8
+7
-9 8
=
-19
=3-1
=2.
|
原式=
+
-12 (1+ 2)(
-1)2
+…+
- 3 2 (
+3
)(2
-3
)2
+
-8 7 (
+8
)(7
- 8
)7
-9 8 (
+8
)(9
-9
) 8
=
-1+2
-3
+2
-4
+…+3
-8
+7
-9 8
=
-19
=3-1
=2.