| 3 | ( | x | + | 3 | ) | = | 4 | ( | x | − | 2 | ) | + | 12 |
| Left side of the equation = | 3 | x | + | 3 | × | 3 |
| = | 3 | x | + | 9 |
| 3 | x | + | 9 | = | 4 | ( | x | − | 2 | ) | + | 12 |
| Right side of the equation = | 4 | x | − | 4 | × | 2 | + | 12 |
| = | 4 | x | − | 8 | + | 12 |
| = | 4 | x | + | 4 |
| 3 | x | + | 9 | = | 4 | x | + | 4 |
| 3 | x | − | 4 | x | = | 4 | − | 9 |
| - | x | = | 4 | − | 9 |
| - | x | = | 4 | − | 9 |
| - | x | = | - | 5 |
| 5 | = | x |
| x | = | 5 |