| 0 | = | 120 | Q | − | 2800000 | − | 90 | Q | − | 120 | × | 5 100 | Q |
| 方程右边 = | 120 | Q | − | 2800000 | − | 90 | Q | − | 6 | Q |
| = | 24 | Q | − | 2800000 |
| 0 | = | 24 | Q | − | 2800000 |
| - | 24 | Q | = | - | 2800000 | − | 0 |
| - | 24 | Q | = | - | 2800000 |
| 2800000 | = | 24 | Q |
| 24 | Q | = | 2800000 |
| Q | = | 2800000 | ÷ | 24 |
| = | 2800000 | × | 1 24 |
| = | 350000 | × | 1 3 |
| Q | = | 350000 3 |
| Q | = | 116666.666667 |