| x |
| x−1 |
| x+3 |
| (x+1)(x−1) |
| (x+1)2 |
| x+3 |
=
| x |
| x−1 |
| x+1 |
| x−1 |
=-
| 1 |
| x−1 |
（2）原式=
| 3−x |
| x−2 |
| 3−x |
| (x+2)(x−2) |
=
| 3−x |
| x−2 |
| (x+2)(x−2) |
| 3−x |
=x+2．
| x |
| x−1 |
| x+3 |
| x2−1 |
| x2+2x+1 |
| x+3 |
| 1 |
| x−2 |
| 3−x |
| x2−4 |
| x |
| x−1 |
| x+3 |
| (x+1)(x−1) |
| (x+1)2 |
| x+3 |
| x |
| x−1 |
| x+1 |
| x−1 |
| 1 |
| x−1 |
| 3−x |
| x−2 |
| 3−x |
| (x+2)(x−2) |
| 3−x |
| x−2 |
| (x+2)(x−2) |
| 3−x |