| 7500 | ( | x | + | 60 | ) | + | 30000 | x | = | 150 | x | ( | x | + | 60 | ) |
| Left side of the equation = | 7500 | x | + | 7500 | × | 60 | + | 30000 | x |
| = | 7500 | x | + | 450000 | + | 30000 | x |
| = | 37500 | x | + | 450000 |
| 37500 | x | + | 450000 | = | 150 | x | ( | x | + | 60 | ) |
| Right side of the equation = | 150 | x | x | + | 150 | x | × | 60 |
| = | 150 | x | x | + | 9000 | x |
| 37500 | x | + | 450000 | = | 150 | x | x | + | 9000 | x |