| 3 | ( | x | − | 3 | ) | − | 5 | ( | 2 | x | + | 1 | ) | = | 4 | − | 3 | ( | x | + | 2 | ) |
| 方程左边 = | 3 | x | − | 3 | × | 3 | − | 5 | ( | 2 | x | + | 1 | ) |
| = | 3 | x | − | 9 | − | 5 | ( | 2 | x | + | 1 | ) |
| = | 3 | x | − | 9 | − | 5 | × | 2 | x | − | 5 | × | 1 |
| = | 3 | x | − | 9 | − | 10 | x | − | 5 |
| = | - | 7 | x | − | 14 |
| - | 7 | x | − | 14 | = | 4 | − | 3 | ( | x | + | 2 | ) |
| 方程右边 = | 4 | − | 3 | x | − | 3 | × | 2 |
| = | 4 | − | 3 | x | − | 6 |
| = | - | 2 | − | 3 | x |
| - | 7 | x | − | 14 | = | - | 2 | − | 3 | x |
| - | 7 | x | + | 3 | x | = | - | 2 | + | 14 |
| - | 4 | x | = | - | 2 | + | 14 |
| - | 4 | x | = | 12 |
| - | 12 | = | 4 | x |
| 4 | x | = | - | 12 |
| x | = | - | 12 | ÷ | 4 |
| = | - | 12 | × | 1 4 |
| = | - | 3 | × | 1 |
| x | = | - | 3 |