| 540 | ÷ | ( | x | − | 20 | ) | = | 780 | ÷ | x |
| Multiply both sides of the equation by: | ( | x | − | 20 | ) | , | x |
| 540 | x | = | 780 | ( | x | − | 20 | ) |
| 540 | x | = | 780 | x | − | 780 | × | 20 |
| 540 | x | = | 780 | x | − | 15600 |
| 540 | x | − | 780 | x | = | - | 15600 |
| - | 240 | x | = | - | 15600 |
| 15600 | = | 240 | x |
| 240 | x | = | 15600 |
| x | = | 15600 | ÷ | 240 |
| = | 15600 | × | 1 240 |
| = | 65 | × | 1 |
| x | = | 65 |