| 4 | x | − | 3 | ( | 20 | − | x | ) | = | 6 | x | − | 7 | ( | 11 | − | x | ) |
| 方程左边 = | 4 | x | − | 3 | × | 20 | + | 3 | x |
| = | 4 | x | − | 60 | + | 3 | x |
| = | 7 | x | − | 60 |
| 7 | x | − | 60 | = | 6 | x | − | 7 | ( | 11 | − | x | ) |
| 方程右边 = | 6 | x | − | 7 | × | 11 | + | 7 | x |
| = | 6 | x | − | 77 | + | 7 | x |
| = | 13 | x | − | 77 |
| 7 | x | − | 60 | = | 13 | x | − | 77 |
| 7 | x | − | 13 | x | = | - | 77 | + | 60 |
| - | 6 | x | = | - | 77 | + | 60 |
| - | 6 | x | = | - | 17 |
| 17 | = | 6 | x |
| 6 | x | = | 17 |
| x | = | 17 | ÷ | 6 |
| = | 17 | × | 1 6 |
| x | = | 17 6 |
| x | = | 2.833333 |