| 9000 | ÷ | x | = | 7500 | ÷ | ( | 220 | − | x | ) |
| Multiply both sides of the equation by: | x | , | ( | 220 | − | x | ) |
| 9000 | ( | 220 | − | x | ) | = | 7500 | x |
| 9000 | × | 220 | − | 9000 | x | = | 7500 | x |
| 1980000 | − | 9000 | x | = | 7500 | x |
| - | 9000 | x | − | 7500 | x | = | - | 1980000 |
| - | 16500 | x | = | - | 1980000 |
| 1980000 | = | 16500 | x |
| 16500 | x | = | 1980000 |
| x | = | 1980000 | ÷ | 16500 |
| = | 1980000 | × | 1 16500 |
| = | 120 | × | 1 |
| x | = | 120 |