| ( | 500 | − | 107 100 | X | − | 187 | ) | × | 500 | = | 1800 |
| 方程左边 = | 500 | × | 500 | − | 107 100 | X | × | 500 | − | 187 | × | 500 |
| = | 250000 | − | 535 | X | − | 93500 |
| = | 156500 | − | 535 | X |
| 156500 | − | 535 | X | = | 1800 |
| - | 535 | X | = | 1800 | − | 156500 |
| - | 535 | X | = | - | 154700 |
| 154700 | = | 535 | X |
| 535 | X | = | 154700 |
| X | = | 154700 | ÷ | 535 |
| = | 154700 | × | 1 535 |
| = | 30940 | × | 1 107 |
| X | = | 30940 107 |
| X | = | 289.158879 |