题目内容
若
+
+
=5,
+
+
=7,则
+
+
=______.
| 1 |
| x |
| 2 |
| y |
| 3 |
| z |
| 3 |
| x |
| 2 |
| y |
| 1 |
| z |
| 1 |
| x |
| 1 |
| y |
| 1 |
| z |
∵
+
+
=5①,
+
+
=7②,
∴①+②得:
+
+
=12,
∴4(
+
+
)=12,
解得:
+
+
=3.
故答案为:3.
| 1 |
| x |
| 2 |
| y |
| 3 |
| z |
| 3 |
| x |
| 2 |
| y |
| 1 |
| z |
∴①+②得:
| 4 |
| x |
| 4 |
| y |
| 4 |
| z |
∴4(
| 1 |
| x |
| 1 |
| y |
| 1 |
| z |
解得:
| 1 |
| x |
| 1 |
| y |
| 1 |
| z |
故答案为:3.
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