| 18 | ÷ | ( | ( | 573 50 | + | X | ) | ÷ | 2 | ) | = | 87 50 |
| 方程两边同时乘以: | ( | ( | 573 50 | + | X | ) | ÷ | 2 | ) |
| 18 | = | 87 50 | ( | ( | 573 50 | + | X | ) | ÷ | 2 | ) |
| 18 | = | 87 50 | ( | 573 50 | + | X | ) | ÷ | 2 |
| 18 | = | 87 100 | ( | 573 50 | + | X | ) |
| 18 | = | 87 100 | × | 573 50 | + | 87 100 | X |
| 18 | = | 49851 5000 | + | 87 100 | X |
| - | 87 100 | X | = | 49851 5000 | − | 18 |
| - | 87 100 | X | = | - | 40149 5000 |
40149 5000 | = | 87 100 | X |
87 100 | X | = | 40149 5000 |
| X | = | 40149 5000 | ÷ | 87 100 |
| = | 40149 5000 | × | 100 87 |
| = | 13383 50 | × | 1 29 |
| X | = | 13383 1450 |
| X | = | 9.229655 |