| 4 | x | x | ÷ | ( | 10 | − | x | ) | ÷ | ( | 1 | − | x | ) | = | 8100 |
| Multiply both sides of the equation by: | ( | 10 | − | x | ) |
| 4 | x | x | ÷ | ( | 1 | − | x | ) | = | 8100 | ( | 10 | − | x | ) |
| 4 | x | x | ÷ | ( | 1 | − | x | ) | = | 8100 | × | 10 | − | 8100 | x |
| 4 | x | x | ÷ | ( | 1 | − | x | ) | = | 81000 | − | 8100 | x |
| Multiply both sides of the equation by: | ( | 1 | − | x | ) |
| 4 | x | x | = | 81000 | ( | 1 | − | x | ) | − | 8100 | x | ( | 1 | − | x | ) |
| 4 | x | x | = | 81000 | × | 1 | − | 81000 | x | − | 8100 | x | ( | 1 | − | x | ) |
| 4 | x | x | = | 81000 | − | 81000 | x | − | 8100 | x | ( | 1 | − | x | ) |
| 4 | x | x | = | 81000 | − | 81000 | x | − | 8100 | x | × | 1 | + | 8100 | x | x |
| 4 | x | x | = | 81000 | − | 81000 | x | − | 8100 | x | + | 8100 | x | x |
| 4 | x | x | = | 81000 | − | 89100 | x | + | 8100 | x | x |