| ( | 14 | − | x | ) | ( | 200 | + | 20 | x | ) | = | 2860 |
| Left side of the equation = | 14 | ( | 200 | + | 20 | x | ) | − | x | ( | 200 | + | 20 | x | ) |
| = | 14 | × | 200 | + | 14 | × | 20 | x | − | x | ( | 200 | + | 20 | x | ) |
| = | 2800 | + | 280 | x | − | x | ( | 200 | + | 20 | x | ) |
| = | 2800 | + | 280 | x | − | x | × | 200 | − | x | × | 20 | x |
| = | 2800 | + | 80 | x | − | x | × | 20 | x |
| 2800 | + | 80 | x | − | x | × | 20 | x | = | 2860 |