| ( | 12 | − | X | ) | ÷ | X | = | - | 19 250 |
| Multiply both sides of the equation by: | X |
| ( | 12 | − | X | ) | = | - | 19 250 | X |
| 12 | − | X | = | - | 19 250 | X |
| - | X | + | 19 250 | X | = | - | 12 |
| - | 231 250 | X | = | - | 12 |
| 12 | = | 231 250 | X |
231 250 | X | = | 12 |
| X | = | 12 | ÷ | 231 250 |
| = | 12 | × | 250 231 |
| = | 4 | × | 250 77 |
| X | = | 1000 77 |
| X | = | 12.987013 |