| 18 | x | ÷ | ( | 100 | − | x | ) | = | 8 | ( | 100 | − | x | ) | ÷ | x |
| Multiply both sides of the equation by: | ( | 100 | − | x | ) | , | x |
| 18 | x | x | = | 8 | ( | 100 | − | x | ) | ( | 100 | − | x | ) |
| 18 | x | x | = | 8 | × | 100 | ( | 100 | − | x | ) | − | 8 | x | ( | 100 | − | x | ) |
| 18 | x | x | = | 800 | ( | 100 | − | x | ) | − | 8 | x | ( | 100 | − | x | ) |
| 18 | x | x | = | 800 | × | 100 | − | 800 | x | − | 8 | x | ( | 100 | − | x | ) |
| 18 | x | x | = | 80000 | − | 800 | x | − | 8 | x | ( | 100 | − | x | ) |
| 18 | x | x | = | 80000 | − | 800 | x | − | 8 | x | × | 100 | + | 8 | x | x |
| 18 | x | x | = | 80000 | − | 800 | x | − | 800 | x | + | 8 | x | x |
| 18 | x | x | = | 80000 | − | 1600 | x | + | 8 | x | x |