| 1200 | ÷ | x | = | 1800 | ÷ | ( | 2 | x | − | 30 | ) |
| Multiply both sides of the equation by: | x | , | ( | 2 | x | − | 30 | ) |
| 1200 | ( | 2 | x | − | 30 | ) | = | 1800 | x |
| 1200 | × | 2 | x | − | 1200 | × | 30 | = | 1800 | x |
| 2400 | x | − | 36000 | = | 1800 | x |
| 2400 | x | − | 1800 | x | = | 36000 |
| 600 | x | = | 36000 |
| x | = | 36000 | ÷ | 600 |
| = | 36000 | × | 1 600 |
| = | 60 | × | 1 |
| x | = | 60 |