| 2800 | = | 330 | × | 4200 | x | ( | 1280 | − | 1 2 | x | ) |
| Right side of the equation = | 1386000 | x | ( | 1280 | − | 1 2 | x | ) |
| 2800 | = | 1386000 | x | ( | 1280 | − | 1 2 | x | ) |
| Right side of the equation = | 1386000 | x | × | 1280 | − | 1386000 | x | × | 1 2 | x |
| = | 1774080000 | x | − | 693000 | x | x |
| 2800 | = | 1774080000 | x | − | 693000 | x | x |