| ( | X | − | 4 | ) | ÷ | 2 5 | − | ( | X | + | 4 | ) | ÷ | 1 2 | = | 1 |
| Left side of the equation = | X | × | 5 2 | − | 4 | × | 5 2 | − | ( | X | + | 4 | ) | × | 2 |
| = | X | × | 5 2 | − | 10 | − | ( | X | + | 4 | ) | × | 2 |
| = | 5 2 | X | − | 10 | − | X | × | 2 | − | 4 | × | 2 |
| = | 5 2 | X | − | 10 | − | X | × | 2 | − | 8 |
| = | 1 2 | X | − | 18 |
1 2 | X | − | 18 | = | 1 |
1 2 | X | = | 1 | + | 18 |
1 2 | X | = | 19 |
| X | = | 19 | ÷ | 1 2 |
| = | 19 | × | 2 |
| X | = | 38 |