| 6000 | ( | 1 | − | x | ) | ( | 1 | − | x | ) | = | 3600 |
| Left side of the equation = | 6000 | × | 1 | ( | 1 | − | x | ) | − | 6000 | x | ( | 1 | − | x | ) |
| = | 6000 | ( | 1 | − | x | ) | − | 6000 | x | ( | 1 | − | x | ) |
| = | 6000 | × | 1 | − | 6000 | x | − | 6000 | x | ( | 1 | − | x | ) |
| = | 6000 | − | 6000 | x | − | 6000 | x | ( | 1 | − | x | ) |
| = | 6000 | − | 6000 | x | − | 6000 | x | × | 1 | + | 6000 | x | x |
| = | 6000 | − | 6000 | x | − | 6000 | x | + | 6000 | x | x |
| = | 6000 | − | 12000 | x | + | 6000 | x | x |
| 6000 | − | 12000 | x | + | 6000 | x | x | = | 3600 |