| 7200 | ÷ | x | = | 10000 | ÷ | ( | 7 10 | + | x | ) |
| Multiply both sides of the equation by: | x | , | ( | 7 10 | + | x | ) |
| 7200 | ( | 7 10 | + | x | ) | = | 10000 | x |
| 7200 | × | 7 10 | + | 7200 | x | = | 10000 | x |
| 5040 | + | 7200 | x | = | 10000 | x |
| 7200 | x | − | 10000 | x | = | - | 5040 |
| - | 2800 | x | = | - | 5040 |
| 5040 | = | 2800 | x |
| 2800 | x | = | 5040 |
| x | = | 5040 | ÷ | 2800 |
| = | 5040 | × | 1 2800 |
| = | 9 | × | 1 5 |
| x | = | 9 5 |
| x | = | 1.8 |