| 1800 | ÷ | x | = | 2250 | ÷ | ( | x | + | 20 | ) |
| Multiply both sides of the equation by: | x | , | ( | x | + | 20 | ) |
| 1800 | ( | x | + | 20 | ) | = | 2250 | x |
| 1800 | x | + | 1800 | × | 20 | = | 2250 | x |
| 1800 | x | + | 36000 | = | 2250 | x |
| 1800 | x | − | 2250 | x | = | - | 36000 |
| - | 450 | x | = | - | 36000 |
| 36000 | = | 450 | x |
| 450 | x | = | 36000 |
| x | = | 36000 | ÷ | 450 |
| = | 36000 | × | 1 450 |
| = | 80 | × | 1 |
| x | = | 80 |