| x | − | ( | x | × | 13 20 | ) | − | ( | x | × | 17 20 | ) | − | 10 | = | 248 |
| 方程左边 = | x | − | x | × | 13 20 | − | ( | x | × | 17 20 | ) | − | 10 |
| = | 7 20 | x | − | ( | x | × | 17 20 | ) | − | 10 |
| = | 7 20 | x | − | x | × | 17 20 | − | 10 |
| = | - | 1 2 | x | − | 10 |
| - | 1 2 | x | − | 10 | = | 248 |
| - | 1 2 | x | = | 248 | + | 10 |
| - | 1 2 | x | = | 258 |
| - | 258 | = | 1 2 | x |
1 2 | x | = | - | 258 |
| x | = | - | 258 | ÷ | 1 2 |
| = | - | 258 | × | 2 |
| x | = | - | 516 |