| ( | X | − | 5000 | ) | × | 10 100 | − | 2520 | = | 3897 50 |
| 方程左边 = | X | × | 10 100 | − | 5000 | × | 10 100 | − | 2520 |
| = | X | × | 10 100 | − | 500 | − | 2520 |
| = | 10 100 | X | − | 3020 |
10 100 | X | − | 3020 | = | 3897 50 |
10 100 | X | = | 3897 50 | + | 3020 |
10 100 | X | = | 154897 50 |
| X | = | 154897 50 | ÷ | 10 100 |
| = | 154897 50 | × | 100 10 |
| = | 154897 | × | 2 10 |
| X | = | 309794 10 |
| X | = | 154897 5 |
| X | = | 30979.4 |