| ( | 36 | ÷ | 2 | ) | X | + | 12 | X | − | 2 | X | × | 13 | = | 100 |
| Left side of the equation = | ( | 36 | ÷ | 2 | ) | X | + | 12 | X | − | 26 | X |
| = | ( | 36 | ÷ | 2 | ) | X | − | 14 | X |
| ( | 36 | ÷ | 2 | ) | X | − | 14 | X | = | 100 |
| Left side of the equation = | 36 | ÷ | 2 | × | X | − | 14 | X |
| = | 18 | X | − | 14 | X |
| = | 4 | X |
| 4 | X | = | 100 |
| X | = | 100 | ÷ | 4 |
| = | 100 | × | 1 4 |
| = | 25 | × | 1 |
| X | = | 25 |