| 440 | ( | 1 | + | x | ) | ( | 1 | + | x | ) | = | 3168 5 |
| Left side of the equation = | 440 | × | 1 | ( | 1 | + | x | ) | + | 440 | x | ( | 1 | + | x | ) |
| = | 440 | ( | 1 | + | x | ) | + | 440 | x | ( | 1 | + | x | ) |
| = | 440 | × | 1 | + | 440 | x | + | 440 | x | ( | 1 | + | x | ) |
| = | 440 | + | 440 | x | + | 440 | x | ( | 1 | + | x | ) |
| = | 440 | + | 440 | x | + | 440 | x | × | 1 | + | 440 | x | x |
| = | 440 | + | 440 | x | + | 440 | x | + | 440 | x | x |
| = | 440 | + | 880 | x | + | 440 | x | x |
| 440 | + | 880 | x | + | 440 | x | x | = | 3168 5 |
| x1= | - | 11 5 |
| x2= | 1 5 |