题干
已知
+
=3，则代数式
的值为____．
| 1 |
| a |
| 1 |
| 2 |
| b |
| 2 |
| a |
| 5 |
| a |
| b |
| + |
| 4 |
| b |
| 4 |
| a |
| b |
| 3 |
| a |
| 6 |
| b |
答案(点此获取答案解析）
﹣
| 1 |
| 2 |
