| 6 | ( | 1 | + | x | ) | ( | 1 | + | x | ) | = | 867 50 |
| Left side of the equation = | 6 | × | 1 | ( | 1 | + | x | ) | + | 6 | x | ( | 1 | + | x | ) |
| = | 6 | ( | 1 | + | x | ) | + | 6 | x | ( | 1 | + | x | ) |
| = | 6 | × | 1 | + | 6 | x | + | 6 | x | ( | 1 | + | x | ) |
| = | 6 | + | 6 | x | + | 6 | x | ( | 1 | + | x | ) |
| = | 6 | + | 6 | x | + | 6 | x | × | 1 | + | 6 | x | x |
| = | 6 | + | 6 | x | + | 6 | x | + | 6 | x | x |
| = | 6 | + | 12 | x | + | 6 | x | x |
| 6 | + | 12 | x | + | 6 | x | x | = | 867 50 |
| x1= | - | 27 10 |
| x2= | 7 10 |