| 2 | ( | x | − | 2 | ) | + | 6 | ( | - | x | + | 12 | ) | = | 4 | ( | x | + | 9 | ) | − | 16 |
| 方程左边 = | 2 | x | − | 2 | × | 2 | + | 6 | ( | - | x | + | 12 | ) |
| = | 2 | x | − | 4 | + | 6 | ( | - | x | + | 12 | ) |
| = | 2 | x | − | 4 | − | 6 | x | + | 6 | × | 12 |
| = | 2 | x | − | 4 | − | 6 | x | + | 72 |
| = | - | 4 | x | + | 68 |
| - | 4 | x | + | 68 | = | 4 | ( | x | + | 9 | ) | − | 16 |
| 方程右边 = | 4 | x | + | 4 | × | 9 | − | 16 |
| = | 4 | x | + | 36 | − | 16 |
| = | 4 | x | + | 20 |
| - | 4 | x | + | 68 | = | 4 | x | + | 20 |
| - | 4 | x | − | 4 | x | = | 20 | − | 68 |
| - | 8 | x | = | 20 | − | 68 |
| - | 8 | x | = | - | 48 |
| 48 | = | 8 | x |
| 8 | x | = | 48 |
| x | = | 48 | ÷ | 8 |
| = | 48 | × | 1 8 |
| = | 6 | × | 1 |
| x | = | 6 |