| 30 | ( | 25 | − | 6 | − | x | ) | ( | x | − | 6 | ) | = | 6300 |
| Left side of the equation = | 30 | × | 25 | ( | x | − | 6 | ) | − | 30 | × | 6 | ( | x | − | 6 | ) | − | 30 | x | ( | x | − | 6 | ) |
| = | 750 | ( | x | − | 6 | ) | − | 180 | ( | x | − | 6 | ) | − | 30 | x | ( | x | − | 6 | ) |
| = | 750 | x | − | 750 | × | 6 | − | 180 | ( | x | − | 6 | ) | − | 30 | x | ( | x | − | 6 | ) |
| = | 750 | x | − | 4500 | − | 180 | ( | x | − | 6 | ) | − | 30 | x | ( | x | − | 6 | ) |
| = | 750 | x | − | 4500 | − | 180 | x | + | 180 | × | 6 | − | 30 | x | ( | x | − | 6 | ) |
| = | 750 | x | − | 4500 | − | 180 | x | + | 1080 | − | 30 | x | ( | x | − | 6 | ) |
| = | 570 | x | − | 3420 | − | 30 | x | ( | x | − | 6 | ) |
| = | 570 | x | − | 3420 | − | 30 | x | x | + | 30 | x | × | 6 |
| = | 570 | x | − | 3420 | − | 30 | x | x | + | 180 | x |
| = | 750 | x | − | 3420 | − | 30 | x | x |
| 750 | x | − | 3420 | − | 30 | x | x | = | 6300 |