| ( | 1000 | + | 2000 | x | ) | ( | 1 | + | x | ) | = | 1320 |
| Left side of the equation = | 1000 | ( | 1 | + | x | ) | + | 2000 | x | ( | 1 | + | x | ) |
| = | 1000 | × | 1 | + | 1000 | x | + | 2000 | x | ( | 1 | + | x | ) |
| = | 1000 | + | 1000 | x | + | 2000 | x | ( | 1 | + | x | ) |
| = | 1000 | + | 1000 | x | + | 2000 | x | × | 1 | + | 2000 | x | x |
| = | 1000 | + | 1000 | x | + | 2000 | x | + | 2000 | x | x |
| = | 1000 | + | 3000 | x | + | 2000 | x | x |
| 1000 | + | 3000 | x | + | 2000 | x | x | = | 1320 |
| x1= | - | 8 5 |
| x2= | 1 10 |