| ( | x | − | 1 | ) | ( | x | − | 1 | ) | − | 4 | ( | x | − | 1 | ) | + | 4 | = | 0 |
| Left side of the equation = | x | ( | x | − | 1 | ) | − | 1 | ( | x | − | 1 | ) | − | 4 | ( | x | − | 1 | ) | + | 4 |
| = | x | x | − | x | × | 1 | − | 1 | ( | x | − | 1 | ) | − | 4 | ( | x | − | 1 | ) | + | 4 |
| = | x | x | − | 1 | x | − | 1 | x | + | 1 | × | 1 | − | 4 | ( | x | − | 1 | ) | + | 4 |
| = | x | x | − | 1 | x | − | 1 | x | + | 1 | − | 4 | ( | x | − | 1 | ) | + | 4 |
| = | x | x | − | 2 | x | + | 5 | − | 4 | ( | x | − | 1 | ) |
| = | x | x | − | 2 | x | + | 5 | − | 4 | x | + | 4 | × | 1 |
| = | x | x | − | 2 | x | + | 5 | − | 4 | x | + | 4 |
| = | x | x | − | 6 | x | + | 9 |
| x | x | − | 6 | x | + | 9 | = | 0 |