| ( | x | − | 50 | ) | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) | = | 12500 |
| Left side of the equation = | x | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) | − | 50 | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) |
| = | x | × | 800 | − | x | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | − | 50 | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) |
| = | x | × | 800 | − | x | ( | x | − | 60 | ) | × | 20 | − | 50 | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) |
| = | 800 | x | − | x | x | × | 20 | + | x | × | 60 | × | 20 | − | 50 | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) |
| = | 800 | x | − | x | x | × | 20 | + | x | × | 1200 | − | 50 | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) |
| = | 2000 | x | − | x | x | × | 20 | − | 50 | ( | 800 | − | ( | x | − | 60 | ) | ÷ | 5 | × | 100 | ) |
| = | 2000 | x | − | x | x | × | 20 | − | 50 | × | 800 | + | 50 | ( | x | − | 60 | ) | ÷ | 5 | × | 100 |
| = | 2000 | x | − | x | x | × | 20 | − | 40000 | + | 1000 | ( | x | − | 60 | ) |
| = | 2000 | x | − | x | x | × | 20 | − | 40000 | + | 1000 | x | − | 1000 | × | 60 |
| = | 2000 | x | − | x | x | × | 20 | − | 40000 | + | 1000 | x | − | 60000 |
| = | 3000 | x | − | x | x | × | 20 | − | 100000 |
| 3000 | x | − | x | x | × | 20 | − | 100000 | = | 12500 |