| ( | 1 | + | x | ) | ( | 1 | + | x | ) | + | ( | 5 | + | x | ) | + | ( | 5 | + | x | ) | = | 0 |
| Left side of the equation = | 1 | ( | 1 | + | x | ) | + | x | ( | 1 | + | x | ) | + | ( | 5 | + | x | ) | + | ( | 5 | + | x | ) |
| = | 1 | × | 1 | + | 1 | x | + | x | ( | 1 | + | x | ) | + | ( | 5 | + | x | ) | + | ( | 5 | + | x | ) |
| = | 1 | + | 1 | x | + | x | ( | 1 | + | x | ) | + | ( | 5 | + | x | ) | + | ( | 5 | + | x | ) |
| = | 1 | + | 1 | x | + | x | × | 1 | + | x | x | + | ( | 5 | + | x | ) | + | ( | 5 | + | x | ) |
| = | 1 | + | 2 | x | + | x | x | + | ( | 5 | + | x | ) | + | ( | 5 | + | x | ) |
| = | 1 | + | 2 | x | + | x | x | + | 5 | + | x | + | ( | 5 | + | x | ) |
| = | 6 | + | 3 | x | + | x | x | + | ( | 5 | + | x | ) |
| = | 6 | + | 3 | x | + | x | x | + | 5 | + | x |
| = | 11 | + | 4 | x | + | x | x |
| 11 | + | 4 | x | + | x | x | = | 0 |