| ( | X | − | 1860 | − | 5000 | ) | × | 1 10 | − | 210 | = | X | − | 12000 |
| 方程左边 = | X | × | 1 10 | − | 1860 | × | 1 10 | − | 5000 | × | 1 10 | − | 210 |
| = | X | × | 1 10 | − | 186 | − | 500 | − | 210 |
| = | 1 10 | X | − | 896 |
1 10 | X | − | 896 | = | X | − | 12000 |
1 10 | X | − | X | = | - | 12000 | + | 896 |
| - | 9 10 | X | = | - | 12000 | + | 896 |
| - | 9 10 | X | = | - | 11104 |
| 11104 | = | 9 10 | X |
9 10 | X | = | 11104 |
| X | = | 11104 | ÷ | 9 10 |
| = | 11104 | × | 10 9 |
| X | = | 111040 9 |
| X | = | 12337.777778 |