| ( | 15 | − | x | ) | ( | 500 | + | 5 | x | ) | = | 4620 |
| Left side of the equation = | 15 | ( | 500 | + | 5 | x | ) | − | x | ( | 500 | + | 5 | x | ) |
| = | 15 | × | 500 | + | 15 | × | 5 | x | − | x | ( | 500 | + | 5 | x | ) |
| = | 7500 | + | 75 | x | − | x | ( | 500 | + | 5 | x | ) |
| = | 7500 | + | 75 | x | − | x | × | 500 | − | x | × | 5 | x |
| = | 7500 | − | 425 | x | − | x | × | 5 | x |
| 7500 | − | 425 | x | − | x | × | 5 | x | = | 4620 |