| ( | 5 | X | + | 1 | ) | ÷ | 2 | − | ( | 7 | X | − | 8 | ) | ÷ | 2 | = | 1 |
| Left side of the equation = | 5 | X | × | 1 2 | + | 1 | × | 1 2 | − | ( | 7 | X | − | 8 | ) | × | 1 2 |
| = | 5 2 | X | + | 1 2 | − | ( | 7 | X | − | 8 | ) | × | 1 2 |
| = | 5 2 | X | + | 1 2 | − | 7 | X | × | 1 2 | + | 8 | × | 1 2 |
| = | 5 2 | X | + | 1 2 | − | 7 2 | X | + | 4 |
| = | - | 1 | X | + | 9 2 |
| - | 1 | X | + | 9 2 | = | 1 |
| - | 1 | X | = | 1 | − | 9 2 |
| - | X | = | 1 | − | 9 2 |
| - | X | = | - | 7 2 |
7 2 | = | X |
| X | = | 7 2 |