| 60 | ( | 100 | − | X | ) | = | 72 | ( | 96 | − | X | ) |
| 方程左边 = | 60 | × | 100 | − | 60 | X |
| = | 6000 | − | 60 | X |
| 6000 | − | 60 | X | = | 72 | ( | 96 | − | X | ) |
| 方程右边 = | 72 | × | 96 | − | 72 | X |
| = | 6912 | − | 72 | X |
| 6000 | − | 60 | X | = | 6912 | − | 72 | X |
| - | 60 | X | + | 72 | X | = | 6912 | − | 6000 |
| 12 | X | = | 6912 | − | 6000 |
| 12 | X | = | 912 |
| X | = | 912 | ÷ | 12 |
| = | 912 | × | 1 12 |
| = | 76 | × | 1 |
| X | = | 76 |