| 2 | ( | 671 10 | − | X | ) | = | 671 10 | − | 9 10 | X |
| 方程左边 = | 2 | × | 671 10 | − | 2 | X |
| = | 671 5 | − | 2 | X |
671 5 | − | 2 | X | = | 671 10 | − | 9 10 | X |
| - | 2 | X | + | 9 10 | X | = | 671 10 | − | 671 5 |
| - | 11 10 | X | = | 671 10 | − | 671 5 |
| - | 11 10 | X | = | - | 671 10 |
671 10 | = | 11 10 | X |
11 10 | X | = | 671 10 |
| X | = | 671 10 | ÷ | 11 10 |
| = | 671 10 | × | 10 11 |
| = | 61 | × | 1 |
| X | = | 61 |