| 200 | x | + | ( | 120 | − | x | ) | ( | - | 3 | x | + | 450 | ) | = | 32160 |
| Left side of the equation = | 200 | x | + | 120 | ( | - | 3 | x | + | 450 | ) | − | x | ( | - | 3 | x | + | 450 | ) |
| = | 200 | x | − | 120 | × | 3 | x | + | 120 | × | 450 | − | x | ( | - | 3 | x | + | 450 | ) |
| = | 200 | x | − | 360 | x | + | 54000 | − | x | ( | - | 3 | x | + | 450 | ) |
| = | - | 160 | x | + | 54000 | − | x | ( | - | 3 | x | + | 450 | ) |
| = | - | 160 | x | + | 54000 | + | x | × | 3 | x | − | x | × | 450 |
| = | - | 610 | x | + | 54000 | + | x | × | 3 | x |
| - | 610 | x | + | 54000 | + | x | × | 3 | x | = | 32160 |