| 3 | − | ( | 13 | − | 6 | ( | 15 | + | 3 | x | ) | ) | = | - | 2 | ( | - | 3 | x | + | 2 | ) |
| 方程左边 = | 3 | − | 13 | + | 6 | ( | 15 | + | 3 | x | ) |
| = | - | 10 | + | 6 | ( | 15 | + | 3 | x | ) |
| = | - | 10 | + | 6 | × | 15 | + | 6 | × | 3 | x |
| = | - | 10 | + | 90 | + | 18 | x |
| = | 80 | + | 18 | x |
| 80 | + | 18 | x | = | - | 2 | ( | - | 3 | x | + | 2 | ) |
| 方程右边 = | 2 | × | 3 | x | − | 2 | × | 2 |
| = | 6 | x | − | 4 |
| 80 | + | 18 | x | = | 6 | x | − | 4 |
| 18 | x | − | 6 | x | = | - | 4 | − | 80 |
| 12 | x | = | - | 4 | − | 80 |
| 12 | x | = | - | 84 |
| x | = | - | 84 | ÷ | 12 |
| = | - | 84 | × | 1 12 |
| = | - | 7 | × | 1 |
| x | = | - | 7 |