| 70 | X | ÷ | ( | 100 | + | X | ) | = | 61 25 |
| Multiply both sides of the equation by: | ( | 100 | + | X | ) |
| 70 | X | = | 61 25 | ( | 100 | + | X | ) |
| 70 | X | = | 61 25 | × | 100 | + | 61 25 | X |
| 70 | X | = | 244 | + | 61 25 | X |
| 70 | X | − | 61 25 | X | = | 244 |
1689 25 | X | = | 244 |
| X | = | 244 | ÷ | 1689 25 |
| = | 244 | × | 25 1689 |
| X | = | 6100 1689 |
| X | = | 3.611604 |