| - | 12 | + | 6 | ( | 3 | + | 4 | ( | 5 | + | 6 | x | ) | ) | = | 9 | ( | 18 | x | − | 2 | ) |
| Left side of the equation = | - | 12 | + | 6 | × | 3 | + | 6 | × | 4 | ( | 5 | + | 6 | x | ) |
| = | - | 12 | + | 18 | + | 24 | ( | 5 | + | 6 | x | ) |
| = | 6 | + | 24 | ( | 5 | + | 6 | x | ) |
| = | 6 | + | 24 | × | 5 | + | 24 | × | 6 | x |
| = | 6 | + | 120 | + | 144 | x |
| = | 126 | + | 144 | x |
| 126 | + | 144 | x | = | 9 | ( | 18 | x | − | 2 | ) |
| Right side of the equation = | 9 | × | 18 | x | − | 9 | × | 2 |
| = | 162 | x | − | 18 |
| 126 | + | 144 | x | = | 162 | x | − | 18 |
| 144 | x | − | 162 | x | = | - | 18 | − | 126 |
| - | 18 | x | = | - | 18 | − | 126 |
| - | 18 | x | = | - | 144 |
| 144 | = | 18 | x |
| 18 | x | = | 144 |
| x | = | 144 | ÷ | 18 |
| = | 144 | × | 1 18 |
| = | 8 | × | 1 |
| x | = | 8 |