| ( | x | − | 6 | ) | ( | 1050 | − | 30 | x | ) | = | 6300 |
| Left side of the equation = | x | ( | 1050 | − | 30 | x | ) | − | 6 | ( | 1050 | − | 30 | x | ) |
| = | x | × | 1050 | − | x | × | 30 | x | − | 6 | ( | 1050 | − | 30 | x | ) |
| = | 1050 | x | − | x | × | 30 | x | − | 6 | × | 1050 | + | 6 | × | 30 | x |
| = | 1050 | x | − | x | × | 30 | x | − | 6300 | + | 180 | x |
| = | 1230 | x | − | x | × | 30 | x | − | 6300 |
| 1230 | x | − | x | × | 30 | x | − | 6300 | = | 6300 |