| X | − | X | × | 13 20000 | − | ( | X | + | 50000 | ) | × | 3 10000 | = | 50000 |
| 方程左边 = | 19987 20000 | X | − | ( | X | + | 50000 | ) | × | 3 10000 |
19987 20000 | X | − | ( | X | + | 50000 | ) | × | 3 10000 | = | 50000 |
| 方程左边 = | 19987 20000 | X | − | X | × | 3 10000 | − | 50000 | × | 3 10000 |
| = | 19987 20000 | X | − | X | × | 3 10000 | − | 15 |
| = | 19981 20000 | X | − | 15 |
19981 20000 | X | − | 15 | = | 50000 |
19981 20000 | X | = | 50000 | + | 15 |
19981 20000 | X | = | 50015 |
| X | = | 50015 | ÷ | 19981 20000 |
| = | 50015 | × | 20000 19981 |
| X | = | 1000300000 19981 |
| X | = | 50062.559431 |