| 80 | ÷ | ( | 80 | + | x | ) | = | 7 100 |
| Multiply both sides of the equation by: | ( | 80 | + | x | ) |
| 80 | = | 7 100 | ( | 80 | + | x | ) |
| 80 | = | 7 100 | × | 80 | + | 7 100 | x |
| 80 | = | 28 5 | + | 7 100 | x |
| - | 7 100 | x | = | 28 5 | − | 80 |
| - | 7 100 | x | = | - | 372 5 |
372 5 | = | 7 100 | x |
7 100 | x | = | 372 5 |
| x | = | 372 5 | ÷ | 7 100 |
| = | 372 5 | × | 100 7 |
| = | 372 | × | 20 7 |
| x | = | 7440 7 |
| x | = | 1062.857143 |