| ( | 4 | x | − | 2 | ) | ( | 4 | x | − | 5 | ) | = | 1 |
| Left side of the equation = | 4 | x | ( | 4 | x | − | 5 | ) | − | 2 | ( | 4 | x | − | 5 | ) |
| = | 4 | x | × | 4 | x | − | 4 | x | × | 5 | − | 2 | ( | 4 | x | − | 5 | ) |
| = | 16 | x | x | − | 20 | x | − | 2 | ( | 4 | x | − | 5 | ) |
| = | 16 | x | x | − | 20 | x | − | 2 | × | 4 | x | + | 2 | × | 5 |
| = | 16 | x | x | − | 20 | x | − | 8 | x | + | 10 |
| = | 16 | x | x | − | 28 | x | + | 10 |
| 16 | x | x | − | 28 | x | + | 10 | = | 1 |