| 10 | ( | 100 | − | 2 | x | ) | ( | 60 | − | x | ) | = | 49500 |
| Left side of the equation = | 10 | × | 100 | ( | 60 | − | x | ) | − | 10 | × | 2 | x | ( | 60 | − | x | ) |
| = | 1000 | ( | 60 | − | x | ) | − | 20 | x | ( | 60 | − | x | ) |
| = | 1000 | × | 60 | − | 1000 | x | − | 20 | x | ( | 60 | − | x | ) |
| = | 60000 | − | 1000 | x | − | 20 | x | ( | 60 | − | x | ) |
| = | 60000 | − | 1000 | x | − | 20 | x | × | 60 | + | 20 | x | x |
| = | 60000 | − | 1000 | x | − | 1200 | x | + | 20 | x | x |
| = | 60000 | − | 2200 | x | + | 20 | x | x |
| 60000 | − | 2200 | x | + | 20 | x | x | = | 49500 |