| 4 | ( | 2 | x | − | 4 | ) | = | 3 | ( | 3 | x | − | 1 | ) | − | 12 |
| Left side of the equation = | 4 | × | 2 | x | − | 4 | × | 4 |
| = | 8 | x | − | 16 |
| 8 | x | − | 16 | = | 3 | ( | 3 | x | − | 1 | ) | − | 12 |
| Right side of the equation = | 3 | × | 3 | x | − | 3 | × | 1 | − | 12 |
| = | 9 | x | − | 3 | − | 12 |
| = | 9 | x | − | 15 |
| 8 | x | − | 16 | = | 9 | x | − | 15 |
| 8 | x | − | 9 | x | = | - | 15 | + | 16 |
| - | x | = | - | 15 | + | 16 |
| - | x | = | - | 15 | + | 16 |
| - | x | = | 1 |
| - | 1 | = | x |
| x | = | - | 1 |