| 450 | ÷ | x | = | 720 | ÷ | ( | x | + | 30 | ) |
| Multiply both sides of the equation by: | x | , | ( | x | + | 30 | ) |
| 450 | ( | x | + | 30 | ) | = | 720 | x |
| 450 | x | + | 450 | × | 30 | = | 720 | x |
| 450 | x | + | 13500 | = | 720 | x |
| 450 | x | − | 720 | x | = | - | 13500 |
| - | 270 | x | = | - | 13500 |
| 13500 | = | 270 | x |
| 270 | x | = | 13500 |
| x | = | 13500 | ÷ | 270 |
| = | 13500 | × | 1 270 |
| = | 50 | × | 1 |
| x | = | 50 |