| 4 | x | − | 12 | − | 6 | x | + | 18 | = | 10 | ÷ | 3 | × | x | − | 6 | x | + | 42 |
| Left side of the equation = | - | 2 | x | + | 6 |
| - | 2 | x | + | 6 | = | 10 | ÷ | 3 | × | x | − | 6 | x | + | 42 |
| Right side of the equation = | 10 3 | x | − | 6 | x | + | 42 |
| = | - | 8 3 | x | + | 42 |
| - | 2 | x | + | 6 | = | - | 8 3 | x | + | 42 |
| - | 2 | x | + | 8 3 | x | = | 42 | − | 6 |
2 3 | x | = | 42 | − | 6 |
2 3 | x | = | 36 |
| x | = | 36 | ÷ | 2 3 |
| = | 36 | × | 3 2 |
| = | 18 | × | 3 |
| x | = | 54 |