| 12 | = | X | + | 1 2 | + | ( | 37 2 | − | X | − | 1 2 | ) | ÷ | 2 |
| Right side of the equation = | X | + | 1 2 | + | 37 2 | × | 1 2 | − | X | × | 1 2 | − | 1 2 | × | 1 2 |
| = | X | + | 1 2 | + | 37 4 | − | X | × | 1 2 | − | 1 4 |
| = | 1 2 | X | + | 19 2 |
| 12 | = | 1 2 | X | + | 19 2 |
| - | 1 2 | X | = | 19 2 | − | 12 |
| - | 1 2 | X | = | - | 5 2 |
5 2 | = | 1 2 | X |
1 2 | X | = | 5 2 |
| X | = | 5 2 | ÷ | 1 2 |
| = | 5 2 | × | 2 |
| = | 5 | × | 1 |
| X | = | 5 |