| 500000000 | = | 48 5 | × | 30000 | × | 640 | + | 48 5 | × | 250 | x | ( | 690 | − | 1 2 | x | ) |
| Right side of the equation = | 184320000 | + | 2400 | x | ( | 690 | − | 1 2 | x | ) |
| 500000000 | = | 184320000 | + | 2400 | x | ( | 690 | − | 1 2 | x | ) |
| Right side of the equation = | 184320000 | + | 2400 | x | × | 690 | − | 2400 | x | × | 1 2 | x |
| = | 184320000 | + | 1656000 | x | − | 1200 | x | x |
| 500000000 | = | 184320000 | + | 1656000 | x | − | 1200 | x | x |