| X | − | 1 10 | X | − | 1 20 | X | − | 3 | = | 642 | + | 3 20 | × | 642 |
| 方程左边 = | 17 20 | X | − | 3 |
17 20 | X | − | 3 | = | 642 | + | 3 20 | × | 642 |
| 方程右边 = | 642 | + | 963 10 |
| = | 7383 10 |
17 20 | X | − | 3 | = | 7383 10 |
17 20 | X | = | 7383 10 | + | 3 |
17 20 | X | = | 7413 10 |
| X | = | 7413 10 | ÷ | 17 20 |
| = | 7413 10 | × | 20 17 |
| = | 7413 | × | 2 17 |
| X | = | 14826 17 |
| X | = | 872.117647 |