| 2 | x | ( | - | 9 | ) | − | 18 | x | ( | 1 | ÷ | 6 | − | 1 | ÷ | 2 | ) | = | 0 |
| 方程左边 = | - | 2 | x | × | 9 | − | 18 | x | ( | 1 | ÷ | 6 | − | 1 | ÷ | 2 | ) |
| = | - | 18 | x | − | 18 | x | ( | 1 | ÷ | 6 | − | 1 | ÷ | 2 | ) |
| = | - | 18 | x | − | 18 | x | × | 1 | ÷ | 6 | + | 18 | x | × | 1 | ÷ | 2 |
| = | - | 18 | x | − | 3 | x | + | 9 | x |
| = | - | 12 | x |
| - | 12 | x | = | 0 |
| - | 0 | = | 12 | x |
| 12 | x | = | - | 0 |
| x | = | - | 0 | ÷ | 12 |
| = | - | 0 | × | 1 12 |
| x | = | 0 |