| 12000 | ( | x | + | 1 | ) | ( | x | + | 1 | ) | = | 14520 |
| Left side of the equation = | 12000 | x | ( | x | + | 1 | ) | + | 12000 | × | 1 | ( | x | + | 1 | ) |
| = | 12000 | x | ( | x | + | 1 | ) | + | 12000 | ( | x | + | 1 | ) |
| = | 12000 | x | x | + | 12000 | x | × | 1 | + | 12000 | ( | x | + | 1 | ) |
| = | 12000 | x | x | + | 12000 | x | + | 12000 | ( | x | + | 1 | ) |
| = | 12000 | x | x | + | 12000 | x | + | 12000 | x | + | 12000 | × | 1 |
| = | 12000 | x | x | + | 12000 | x | + | 12000 | x | + | 12000 |
| = | 12000 | x | x | + | 24000 | x | + | 12000 |
| 12000 | x | x | + | 24000 | x | + | 12000 | = | 14520 |
| x1= | - | 21 10 |
| x2= | 1 10 |