| 575 | − | 450 | − | x | ( | 1 | − | 25 100 | ) | = | 80 |
| Left side of the equation = | 125 | − | x | ( | 1 | − | 25 100 | ) |
| 125 | − | x | ( | 1 | − | 25 100 | ) | = | 80 |
| Left side of the equation = | 125 | − | x | × | 1 | + | x | × | 25 100 |
| = | 125 | − | 3 4 | x |
| 125 | − | 3 4 | x | = | 80 |
| - | 3 4 | x | = | 80 | − | 125 |
| - | 3 4 | x | = | - | 45 |
| 45 | = | 3 4 | x |
3 4 | x | = | 45 |
| x | = | 45 | ÷ | 3 4 |
| = | 45 | × | 4 3 |
| = | 15 | × | 4 |
| x | = | 60 |