| 77325 | − | 15 | x | = | 40 | ( | 28 | x | + | 32 | ) |
| 方程右边 = | 40 | × | 28 | x | + | 40 | × | 32 |
| = | 1120 | x | + | 1280 |
| 77325 | − | 15 | x | = | 1120 | x | + | 1280 |
| - | 15 | x | − | 1120 | x | = | 1280 | − | 77325 |
| - | 1135 | x | = | 1280 | − | 77325 |
| - | 1135 | x | = | - | 76045 |
| 76045 | = | 1135 | x |
| 1135 | x | = | 76045 |
| x | = | 76045 | ÷ | 1135 |
| = | 76045 | × | 1 1135 |
| = | 15209 | × | 1 227 |
| x | = | 15209 227 |
| x | = | 67 |