| 2 | ( | 2 | − | x | ) | + | ( | 4 | x | − | 2 | ) | = | 7 | ( | x | − | 4 | ) |
| 方程左边 = | 2 | × | 2 | − | 2 | x | + | ( | 4 | x | − | 2 | ) |
| = | 4 | − | 2 | x | + | ( | 4 | x | − | 2 | ) |
| = | 4 | − | 2 | x | + | 4 | x | − | 2 |
| = | 2 | + | 2 | x |
| 2 | + | 2 | x | = | 7 | ( | x | − | 4 | ) |
| 方程右边 = | 7 | x | − | 7 | × | 4 |
| = | 7 | x | − | 28 |
| 2 | + | 2 | x | = | 7 | x | − | 28 |
| 2 | x | − | 7 | x | = | - | 28 | − | 2 |
| - | 5 | x | = | - | 28 | − | 2 |
| - | 5 | x | = | - | 30 |
| 30 | = | 5 | x |
| 5 | x | = | 30 |
| x | = | 30 | ÷ | 5 |
| = | 30 | × | 1 5 |
| = | 6 | × | 1 |
| x | = | 6 |