| 12 | × | 2 | + | 5 | + | X | + | 3 | ( | 5 | + | 3 | − | X | ) | = | 0 |
| Left side of the equation = | 24 | + | 5 | + | X | + | 3 | ( | 5 | + | 3 | − | X | ) |
| = | 29 | + | X | + | 3 | ( | 5 | + | 3 | − | X | ) |
| 29 | + | X | + | 3 | ( | 5 | + | 3 | − | X | ) | = | 0 |
| Left side of the equation = | 29 | + | X | + | 3 | × | 5 | + | 3 | × | 3 | − | 3 | X |
| = | 29 | + | X | + | 15 | + | 9 | − | 3 | X |
| = | 53 | − | 2 | X |
| 53 | − | 2 | X | = | 0 |
| - | 2 | X | = | 0 | − | 53 |
| - | 2 | X | = | - | 53 |
| 53 | = | 2 | X |
| 2 | X | = | 53 |
| X | = | 53 | ÷ | 2 |
| = | 53 | × | 1 2 |
| X | = | 53 2 |
| X | = | 26.5 |