题干
已知a、b、c均是不等于0的有理数，则
+
+
+
+
+
+
的值为____
| a |
| a |
| b |
| b |
| c |
| c |
| a |
| b |
| a |
| b |
| b |
| c |
| b |
| c |
| a |
| c |
| a |
| c |
| a |
| b |
| c |
| a |
| b |
| c |
答案(点此获取答案解析）
7或﹣1
