| ( | 5000 | + | X | ) | ( | 1 | − | 20 100 | ) | × | 20 100 | = | X |
| 方程左边 = | 5000 | ( | 1 | − | 20 100 | ) | × | 20 100 | + | X | ( | 1 | − | 20 100 | ) | × | 20 100 |
| = | 1000 | ( | 1 | − | 20 100 | ) | + | X | ( | 1 | − | 20 100 | ) | × | 20 100 |
| = | 1000 | × | 1 | − | 1000 | × | 20 100 | + | X | ( | 1 | − | 20 100 | ) | × | 20 100 |
| = | 1000 | − | 200 | + | X | ( | 1 | − | 20 100 | ) | × | 20 100 |
| = | 800 | + | X | ( | 1 | − | 20 100 | ) | × | 20 100 |
| = | 800 | + | X | × | 1 | × | 20 100 | − | X | × | 20 100 | × | 20 100 |
| = | 800 | + | X | × | 1 5 | − | X | × | 1 25 |
| = | 800 | + | 4 25 | X |
| 800 | + | 4 25 | X | = | X |
4 25 | X | − | X | = | - | 800 |
| - | 21 25 | X | = | - | 800 |
| 800 | = | 21 25 | X |
21 25 | X | = | 800 |
| X | = | 800 | ÷ | 21 25 |
| = | 800 | × | 25 21 |
| X | = | 20000 21 |
| X | = | 952.380952 |