| a |
| b(a−b) |
| b |
| a(a−b) |
| 2ab+a2+b2 |
| 2ab |
=
| a2−b2 |
| ab(a−b) |
| 2ab |
| (a+b)2 |
=
| (a+b)(a−b) |
| ab(a−b) |
| 2ab |
| (a+b)2 |
=
| 2 |
| a+b |
当a=-1+
| 3 |
| 3 |
原式=
| 2 |
| −2 |
| a |
| ab−b2 |
| b |
| a2−ab |
| a2+b2 |
| 2ab |
| 3 |
| 3 |
| a |
| b(a−b) |
| b |
| a(a−b) |
| 2ab+a2+b2 |
| 2ab |
| a2−b2 |
| ab(a−b) |
| 2ab |
| (a+b)2 |
| (a+b)(a−b) |
| ab(a−b) |
| 2ab |
| (a+b)2 |
| 2 |
| a+b |
| 3 |
| 3 |
| 2 |
| −2 |