| 8000 | ÷ | x | = | 10400 | ÷ | x | + | 120 |
| Multiply both sides of the equation by: | x |
| 8000 | = | 10400 | ÷ | 1 | × | 1 | + | 120 | x |
| - | 120 | x | = | 10400 | ÷ | 1 | × | 1 | − | 8000 |
| - | 120 | x | = | 10400 | − | 8000 |
| - | 120 | x | = | 2400 |
| - | 2400 | = | 120 | x |
| 120 | x | = | - | 2400 |
| x | = | - | 2400 | ÷ | 120 |
| = | - | 2400 | × | 1 120 |
| = | - | 20 | × | 1 |
| x | = | - | 20 |