| 40 | ÷ | ( | x | − | 40 | ) | = | 60 | ÷ | ( | x | + | 60 | ) |
| Multiply both sides of the equation by: | ( | x | − | 40 | ) | , | ( | x | + | 60 | ) |
| 40 | ( | x | + | 60 | ) | = | 60 | ( | x | − | 40 | ) |
| 40 | x | + | 40 | × | 60 | = | 60 | ( | x | − | 40 | ) |
| 40 | x | + | 40 | × | 60 | = | 60 | x | − | 60 | × | 40 |
| 40 | x | + | 2400 | = | 60 | x | − | 2400 |
| 40 | x | − | 60 | x | = | - | 2400 | − | 2400 |
| - | 20 | x | = | - | 2400 | − | 2400 |
| - | 20 | x | = | - | 4800 |
| 4800 | = | 20 | x |
| 20 | x | = | 4800 |
| x | = | 4800 | ÷ | 20 |
| = | 4800 | × | 1 20 |
| = | 240 | × | 1 |
| x | = | 240 |