| ( | 100 | − | 45 | ) | ÷ | ( | 100 | − | X | ) | = | 6 5 |
| Multiply both sides of the equation by: | ( | 100 | − | X | ) |
| ( | 100 | − | 45 | ) | = | 6 5 | ( | 100 | − | X | ) |
| 100 | − | 45 | = | 6 5 | ( | 100 | − | X | ) |
| 100 | − | 45 | = | 6 5 | × | 100 | − | 6 5 | X |
| 100 | − | 45 | = | 120 | − | 6 5 | X |
| 55 | = | 120 | − | 6 5 | X |
6 5 | X | = | 120 | − | 55 |
6 5 | X | = | 65 |
| X | = | 65 | ÷ | 6 5 |
| = | 65 | × | 5 6 |
| X | = | 325 6 |
| X | = | 54.166667 |