| ( | 25 | + | x | ) | ( | 150 | − | 2 | x | ) | = | 4800 |
| Left side of the equation = | 25 | ( | 150 | − | 2 | x | ) | + | x | ( | 150 | − | 2 | x | ) |
| = | 25 | × | 150 | − | 25 | × | 2 | x | + | x | ( | 150 | − | 2 | x | ) |
| = | 3750 | − | 50 | x | + | x | ( | 150 | − | 2 | x | ) |
| = | 3750 | − | 50 | x | + | x | × | 150 | − | x | × | 2 | x |
| = | 3750 | + | 100 | x | − | x | × | 2 | x |
| 3750 | + | 100 | x | − | x | × | 2 | x | = | 4800 |