| ( | x | − | 500 | ) | ( | 100 | − | x | ÷ | 100 | ) | − | x | = | 404000 |
| Left side of the equation = | x | ( | 100 | − | x | ÷ | 100 | ) | − | 500 | ( | 100 | − | x | ÷ | 100 | ) | − | x |
| = | x | × | 100 | − | x | x | ÷ | 100 | − | 500 | ( | 100 | − | x | ÷ | 100 | ) | − | x |
| = | 99 | x | − | x | x | × | 1 100 | − | 500 | ( | 100 | − | x | ÷ | 100 | ) |
| = | 99 | x | − | x | x | × | 1 100 | − | 500 | × | 100 | + | 500 | x | ÷ | 100 |
| = | 99 | x | − | x | x | × | 1 100 | − | 50000 | + | 5 | x |
| = | 104 | x | − | x | x | × | 1 100 | − | 50000 |
| 104 | x | − | x | x | × | 1 100 | − | 50000 | = | 404000 |