81 50 | = | f | ÷ | ( | f | − | 5 2 | ) |
| Multiply both sides of the equation by: | ( | f | − | 5 2 | ) |
81 50 | ( | f | − | 5 2 | ) | = | f |
81 50 | f | − | 81 50 | × | 5 2 | = | f |
81 50 | f | − | 81 20 | = | f |
81 50 | f | − | f | = | 81 20 |
31 50 | f | = | 81 20 |
| f | = | 81 20 | ÷ | 31 50 |
| = | 81 20 | × | 50 31 |
| = | 81 2 | × | 5 31 |
| f | = | 405 62 |
| f | = | 6.532258 |