| X | − | ( | 500 | + | 600 | + | 3 10 | X | + | 1 2 | X | × | 1 5 | ) | = | 7 10 | X |
| 方程左边 = | X | − | 500 | − | 600 | − | 3 10 | X | − | 1 2 | X | × | 1 5 |
| = | X | − | 500 | − | 600 | − | 3 10 | X | − | 1 10 | X |
| = | 3 5 | X | − | 1100 |
3 5 | X | − | 1100 | = | 7 10 | X |
3 5 | X | − | 7 10 | X | = | 1100 |
| - | 1 10 | X | = | 1100 |
| - | 1100 | = | 1 10 | X |
1 10 | X | = | - | 1100 |
| X | = | - | 1100 | ÷ | 1 10 |
| = | - | 1100 | × | 10 |
| X | = | - | 11000 |