| - | 2 | ( | x | + | 1 | ) | + | 2 | ( | - | 12 | x | − | 11 | ) | + | 1 | = | 3 |
| 方程左边 = | - | 2 | x | − | 2 | × | 1 | + | 2 | ( | - | 12 | x | − | 11 | ) | + | 1 |
| = | - | 2 | x | − | 2 | + | 2 | ( | - | 12 | x | − | 11 | ) | + | 1 |
| = | - | 2 | x | − | 1 | + | 2 | ( | - | 12 | x | − | 11 | ) |
| = | - | 2 | x | − | 1 | − | 2 | × | 12 | x | − | 2 | × | 11 |
| = | - | 2 | x | − | 1 | − | 24 | x | − | 22 |
| = | - | 26 | x | − | 23 |
| - | 26 | x | − | 23 | = | 3 |
| - | 26 | x | = | 3 | + | 23 |
| - | 26 | x | = | 26 |
| - | 26 | = | 26 | x |
| 26 | x | = | - | 26 |
| x | = | - | 26 | ÷ | 26 |
| = | - | 26 | × | 1 26 |
| = | - | 1 | × | 1 |
| x | = | - | 1 |