| 2 | ( | 10 | − | 1 2 | X | ) | = | - | ( | 3 | X | + | 4 | ) |
| Left side of the equation = | 2 | × | 10 | − | 2 | × | 1 2 | X |
| = | 20 | − | 1 | X |
| 20 | − | 1 | X | = | - | ( | 3 | X | + | 4 | ) |
| Right side of the equation = | - | 3 | X | − | 4 |
| 20 | − | 1 | X | = | - | 3 | X | − | 4 |
| - | 1 | X | + | 3 | X | = | - | 4 | − | 20 |
| 2 | X | = | - | 4 | − | 20 |
| 2 | X | = | - | 24 |
| X | = | - | 24 | ÷ | 2 |
| = | - | 24 | × | 1 2 |
| = | - | 12 | × | 1 |
| X | = | - | 12 |