| ( | 2900 | − | x | ) | ( | 8 | + | 1 8 | x | ) | = | 5000 |
| Left side of the equation = | 2900 | ( | 8 | + | 1 8 | x | ) | − | x | ( | 8 | + | 1 8 | x | ) |
| = | 2900 | × | 8 | + | 2900 | × | 1 8 | x | − | x | ( | 8 | + | 1 8 | x | ) |
| = | 23200 | + | 725 2 | x | − | x | ( | 8 | + | 1 8 | x | ) |
| = | 23200 | + | 725 2 | x | − | x | × | 8 | − | x | × | 1 8 | x |
| = | 23200 | + | 709 2 | x | − | x | × | 1 8 | x |
| 23200 | + | 709 2 | x | − | x | × | 1 8 | x | = | 5000 |