| 3 | ( | x | − | 1 | ) | ( | 3 | − | x | ) | = | 0 |
| Left side of the equation = | 3 | x | ( | 3 | − | x | ) | − | 3 | × | 1 | ( | 3 | − | x | ) |
| = | 3 | x | ( | 3 | − | x | ) | − | 3 | ( | 3 | − | x | ) |
| = | 3 | x | × | 3 | − | 3 | x | x | − | 3 | ( | 3 | − | x | ) |
| = | 9 | x | − | 3 | x | x | − | 3 | ( | 3 | − | x | ) |
| = | 9 | x | − | 3 | x | x | − | 3 | × | 3 | + | 3 | x |
| = | 9 | x | − | 3 | x | x | − | 9 | + | 3 | x |
| = | 12 | x | − | 3 | x | x | − | 9 |
| 12 | x | − | 3 | x | x | − | 9 | = | 0 |