| ( | 2 | − | x | ) | ( | - | 1 | − | x | ) | − | 10 | = | 0 |
| Left side of the equation = | 2 | ( | - | 1 | − | x | ) | − | x | ( | - | 1 | − | x | ) | − | 10 |
| = | - | 2 | × | 1 | − | 2 | x | − | x | ( | - | 1 | − | x | ) | − | 10 |
| = | - | 2 | − | 2 | x | − | x | ( | - | 1 | − | x | ) | − | 10 |
| = | - | 12 | − | 2 | x | − | x | ( | - | 1 | − | x | ) |
| = | - | 12 | − | 2 | x | + | x | × | 1 | + | x | x |
| = | - | 12 | − | 1 | x | + | x | x |
| - | 12 | − | 1 | x | + | x | x | = | 0 |