| ( | ( | X | + | 3900 | ) | ÷ | 3900 | ) | × | 397 1000 | = | 31 2 |
| 方程左边 = | ( | X | + | 3900 | ) | ÷ | 3900 | × | 397 1000 |
| = | ( | X | + | 3900 | ) | × | 397 3900000 |
| = | X | × | 397 3900000 | + | 3900 | × | 397 3900000 |
| = | X | × | 397 3900000 | + | 397 1000 |
397 3900000 | X | + | 397 1000 | = | 31 2 |
397 3900000 | X | = | 31 2 | − | 397 1000 |
397 3900000 | X | = | 15103 1000 |
| X | = | 15103 1000 | ÷ | 397 3900000 |
| = | 15103 1000 | × | 3900000 397 |
| = | 15103 | × | 3900 397 |
| X | = | 58901700 397 |
| X | = | 148367.002519 |