题干
化简：
÷（a﹣b）•
= ____ ；计算：
+
﹣
=____
| a |
| - |
| b |
| a |
| + |
| b |
| 1 |
| a |
| - |
| b |
| m |
| + |
| 2 |
| n |
| n |
| - |
| m |
| n |
| m |
| - |
| n |
| 2 |
| m |
| n |
| - |
| m |
答案(点此获取答案解析）
{#/
