| ( | 8 | − | x | ) | ( | 200 | + | 50 | x | ) | = | 1750 |
| Left side of the equation = | 8 | ( | 200 | + | 50 | x | ) | − | x | ( | 200 | + | 50 | x | ) |
| = | 8 | × | 200 | + | 8 | × | 50 | x | − | x | ( | 200 | + | 50 | x | ) |
| = | 1600 | + | 400 | x | − | x | ( | 200 | + | 50 | x | ) |
| = | 1600 | + | 400 | x | − | x | × | 200 | − | x | × | 50 | x |
| = | 1600 | + | 200 | x | − | x | × | 50 | x |
| 1600 | + | 200 | x | − | x | × | 50 | x | = | 1750 |