| ( | ( | 500 | − | X | ) | ÷ | X | ) | × | 100 | = | 5 2 |
| ( | 500 | − | X | ) | ÷ | X | × | 100 | = | 5 2 |
| 方程两边同时乘以: | X |
| ( | 500 | − | X | ) | × | 100 | = | 5 2 | X |
| 500 | × | 100 | − | X | × | 100 | = | 5 2 | X |
| 50000 | − | X | × | 100 | = | 5 2 | X |
| - | 100 | X | − | 5 2 | X | = | - | 50000 |
| - | 205 2 | X | = | - | 50000 |
| 50000 | = | 205 2 | X |
205 2 | X | = | 50000 |
| X | = | 50000 | ÷ | 205 2 |
| = | 50000 | × | 2 205 |
| = | 10000 | × | 2 41 |
| X | = | 20000 41 |
| X | = | 487.804878 |