| ( | x | − | 4 | ) | ( | x | − | 4 | ) | − | 2 | ( | x | − | 4 | ) | + | 1 | = | 0 |
| Left side of the equation = | x | ( | x | − | 4 | ) | − | 4 | ( | x | − | 4 | ) | − | 2 | ( | x | − | 4 | ) | + | 1 |
| = | x | x | − | x | × | 4 | − | 4 | ( | x | − | 4 | ) | − | 2 | ( | x | − | 4 | ) | + | 1 |
| = | x | x | − | 4 | x | − | 4 | x | + | 4 | × | 4 | − | 2 | ( | x | − | 4 | ) | + | 1 |
| = | x | x | − | 4 | x | − | 4 | x | + | 16 | − | 2 | ( | x | − | 4 | ) | + | 1 |
| = | x | x | − | 8 | x | + | 17 | − | 2 | ( | x | − | 4 | ) |
| = | x | x | − | 8 | x | + | 17 | − | 2 | x | + | 2 | × | 4 |
| = | x | x | − | 8 | x | + | 17 | − | 2 | x | + | 8 |
| = | x | x | − | 10 | x | + | 25 |
| x | x | − | 10 | x | + | 25 | = | 0 |