| ( | 50 | − | X | ) | ÷ | ( | 0 | − | X | ) | = | - | 12 5 |
| 方程两边同时乘以: | ( | 0 | − | X | ) |
| ( | 50 | − | X | ) | = | - | 12 5 | ( | 0 | − | X | ) |
| 50 | − | X | = | - | 12 5 | ( | 0 | − | X | ) |
| 50 | − | X | = | - | 12 5 | × | 0 | + | 12 5 | X |
| 50 | − | X | = | - | 0 | + | 12 5 | X |
| - | X | − | 12 5 | X | = | - | 50 |
| - | 17 5 | X | = | - | 50 |
| 50 | = | 17 5 | X |
17 5 | X | = | 50 |
| X | = | 50 | ÷ | 17 5 |
| = | 50 | × | 5 17 |
| X | = | 250 17 |
| X | = | 14.705882 |