| ( | 14 | − | x | ) | ( | 30 | x | + | 300 | ) | = | 6300 |
| Left side of the equation = | 14 | ( | 30 | x | + | 300 | ) | − | x | ( | 30 | x | + | 300 | ) |
| = | 14 | × | 30 | x | + | 14 | × | 300 | − | x | ( | 30 | x | + | 300 | ) |
| = | 420 | x | + | 4200 | − | x | ( | 30 | x | + | 300 | ) |
| = | 420 | x | + | 4200 | − | x | × | 30 | x | − | x | × | 300 |
| = | 120 | x | + | 4200 | − | x | × | 30 | x |
| 120 | x | + | 4200 | − | x | × | 30 | x | = | 6300 |