| ( | 3 | − | 2 | m | ) | ( | 3 | − | m | ) | = | - | m | ( | 2 | ) | + | 3 | m | + | 4 |
| 方程左边 = | 3 | ( | 3 | − | m | ) | − | 2 | m | ( | 3 | − | m | ) |
| = | 3 | × | 3 | − | 3 | m | − | 2 | m | ( | 3 | − | m | ) |
| = | 9 | − | 3 | m | − | 2 | m | ( | 3 | − | m | ) |
| = | 9 | − | 3 | m | − | 2 | m | × | 3 | + | 2 | m | m |
| = | 9 | − | 3 | m | − | 6 | m | + | 2 | m | m |
| = | 9 | − | 9 | m | + | 2 | m | m |
| 9 | − | 9 | m | + | 2 | m | m | = | - | m | ( | 2 | ) | + | 3 | m | + | 4 |
| 方程右边 = | - | m | × | 2 | + | 3 | m | + | 4 |
| = | 1 | m | + | 4 |
| 9 | − | 9 | m | + | 2 | m | m | = | 1 | m | + | 4 |