| x | − | ( | x | × | 3 5 | ) | − | ( | x | × | 17 20 | ) | − | 10 | = | 278 |
| 方程左边 = | x | − | x | × | 3 5 | − | ( | x | × | 17 20 | ) | − | 10 |
| = | 2 5 | x | − | ( | x | × | 17 20 | ) | − | 10 |
| = | 2 5 | x | − | x | × | 17 20 | − | 10 |
| = | - | 9 20 | x | − | 10 |
| - | 9 20 | x | − | 10 | = | 278 |
| - | 9 20 | x | = | 278 | + | 10 |
| - | 9 20 | x | = | 288 |
| - | 288 | = | 9 20 | x |
9 20 | x | = | - | 288 |
| x | = | - | 288 | ÷ | 9 20 |
| = | - | 288 | × | 20 9 |
| = | - | 32 | × | 20 |
| x | = | - | 640 |