题目内容
(2013•南京)计算(1-
-
-
-
)(
+
+
+
+
)-(1-
-
-
-
-
)(
+
+
+
)的结果是
.
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
6 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
6 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
6 |
1 |
6 |
分析:设a=1-
-
-
-
,b=
+
+
+
,然后根据整式的乘法与加减混合运算进行计算即可得解.
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
解答:解:设a=1-
-
-
-
,b=
+
+
+
,
则原式=a(b+
)-(a-
)•b
=ab+
a-ab+
b
=
(a+b),
∵a+b=1-
-
-
-
+
+
+
+
=1,
∴原式=
.
故答案为:
.
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
则原式=a(b+
1 |
6 |
1 |
6 |
=ab+
1 |
6 |
1 |
6 |
=
1 |
6 |
∵a+b=1-
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
1 |
2 |
1 |
3 |
1 |
4 |
1 |
5 |
∴原式=
1 |
6 |
故答案为:
1 |
6 |
点评:本题考查了整式的混合运算,利用换元法可以使书写更简便且形象直观.
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