| ( | 50 | x | + | 50 | ) | ( | 8 | − | x | ) | = | 300 |
| Left side of the equation = | 50 | x | ( | 8 | − | x | ) | + | 50 | ( | 8 | − | x | ) |
| = | 50 | x | × | 8 | − | 50 | x | x | + | 50 | ( | 8 | − | x | ) |
| = | 400 | x | − | 50 | x | x | + | 50 | ( | 8 | − | x | ) |
| = | 400 | x | − | 50 | x | x | + | 50 | × | 8 | − | 50 | x |
| = | 400 | x | − | 50 | x | x | + | 400 | − | 50 | x |
| = | 350 | x | − | 50 | x | x | + | 400 |
| 350 | x | − | 50 | x | x | + | 400 | = | 300 |