| ( | 100 | − | 2 | x | ) | ( | x | − | 30 | ) | = | 150 |
| Left side of the equation = | 100 | ( | x | − | 30 | ) | − | 2 | x | ( | x | − | 30 | ) |
| = | 100 | x | − | 100 | × | 30 | − | 2 | x | ( | x | − | 30 | ) |
| = | 100 | x | − | 3000 | − | 2 | x | ( | x | − | 30 | ) |
| = | 100 | x | − | 3000 | − | 2 | x | x | + | 2 | x | × | 30 |
| = | 100 | x | − | 3000 | − | 2 | x | x | + | 60 | x |
| = | 160 | x | − | 3000 | − | 2 | x | x |
| 160 | x | − | 3000 | − | 2 | x | x | = | 150 |