| 2 | ( | 2 | ( | - | ( | 3 | x | + | 10 | ) | − | 3 | ) | + | 12 | ) | + | 2 | = | 9 | x | + | 142 |
| Left side of the equation = | 2 | × | 2 | ( | - | ( | 3 | x | + | 10 | ) | − | 3 | ) | + | 2 | × | 12 | + | 2 |
| = | 4 | ( | - | ( | 3 | x | + | 10 | ) | − | 3 | ) | + | 24 | + | 2 |
| = | 4 | ( | - | ( | 3 | x | + | 10 | ) | − | 3 | ) | + | 26 |
| = | - | 4 | ( | 3 | x | + | 10 | ) | − | 4 | × | 3 | + | 26 |
| = | - | 4 | ( | 3 | x | + | 10 | ) | − | 12 | + | 26 |
| = | - | 4 | ( | 3 | x | + | 10 | ) | + | 14 |
| = | - | 4 | × | 3 | x | − | 4 | × | 10 | + | 14 |
| = | - | 12 | x | − | 40 | + | 14 |
| = | - | 12 | x | − | 26 |
| - | 12 | x | − | 26 | = | 9 | x | + | 142 |
| - | 12 | x | − | 9 | x | = | 142 | + | 26 |
| - | 21 | x | = | 142 | + | 26 |
| - | 21 | x | = | 168 |
| - | 168 | = | 21 | x |
| 21 | x | = | - | 168 |
| x | = | - | 168 | ÷ | 21 |
| = | - | 168 | × | 1 21 |
| = | - | 8 | × | 1 |
| x | = | - | 8 |