| 50 | + | X | − | ( | X | × | 1 100 | ) | − | 1200 | × | 1 100 | = | 900 |
| 方程左边 = | 50 | + | X | − | ( | X | × | 1 100 | ) | − | 12 |
| = | 38 | + | X | − | ( | X | × | 1 100 | ) |
| 38 | + | X | − | ( | X | × | 1 100 | ) | = | 900 |
| 方程左边 = | 38 | + | X | − | X | × | 1 100 |
| = | 38 | + | 99 100 | X |
| 38 | + | 99 100 | X | = | 900 |
99 100 | X | = | 900 | − | 38 |
99 100 | X | = | 862 |
| X | = | 862 | ÷ | 99 100 |
| = | 862 | × | 100 99 |
| X | = | 86200 99 |
| X | = | 870.707071 |