| 5 | ( | x | + | 6 | ) | + | 2 | x | = | 3 | ( | - | 9 | + | x | ) |
| 方程左边 = | 5 | x | + | 5 | × | 6 | + | 2 | x |
| = | 5 | x | + | 30 | + | 2 | x |
| = | 7 | x | + | 30 |
| 7 | x | + | 30 | = | 3 | ( | - | 9 | + | x | ) |
| 方程右边 = | - | 3 | × | 9 | + | 3 | x |
| = | - | 27 | + | 3 | x |
| 7 | x | + | 30 | = | - | 27 | + | 3 | x |
| 7 | x | − | 3 | x | = | - | 27 | − | 30 |
| 4 | x | = | - | 27 | − | 30 |
| 4 | x | = | - | 57 |
| x | = | - | 57 | ÷ | 4 |
| = | - | 57 | × | 1 4 |
| x | = | - | 57 4 |
| x | = | - 14.25 |