| x | − | x | ÷ | 21 20 | × | 28 25 | − | x | × | 1 2000 | − | ( | x | − | x | ÷ | 21 20 | ) | × | 5 100 | = | 4500 |
| Left side of the equation = | x | − | x | × | 16 15 | − | x | × | 1 2000 | − | ( | x | − | x | ÷ | 21 20 | ) | × | 5 100 |
| = | - | 403 6000 | x | − | ( | x | − | x | ÷ | 21 20 | ) | × | 5 100 |
| - | 403 6000 | x | − | ( | x | − | x | ÷ | 21 20 | ) | × | 5 100 | = | 4500 |
| Left side of the equation = | - | 403 6000 | x | − | x | × | 5 100 | + | x | ÷ | 21 20 | × | 5 100 |
| = | - | 403 6000 | x | − | x | × | 5 100 | + | x | × | 1 21 |
| = | - | 2921 42000 | x |
| - | 2921 42000 | x | = | 4500 |
| - | 4500 | = | 2921 42000 | x |
2921 42000 | x | = | - | 4500 |
| x | = | - | 4500 | ÷ | 2921 42000 |
| = | - | 4500 | × | 42000 2921 |
| x | = | - | 189000000 2921 |
| x | = | - 64703.868538 |