| 11 | ( | X | − | 2 | ) | = | 13 | ( | X | − | 4 | ) |
| Left side of the equation = | 11 | X | − | 11 | × | 2 |
| = | 11 | X | − | 22 |
| 11 | X | − | 22 | = | 13 | ( | X | − | 4 | ) |
| Right side of the equation = | 13 | X | − | 13 | × | 4 |
| = | 13 | X | − | 52 |
| 11 | X | − | 22 | = | 13 | X | − | 52 |
| 11 | X | − | 13 | X | = | - | 52 | + | 22 |
| - | 2 | X | = | - | 52 | + | 22 |
| - | 2 | X | = | - | 30 |
| 30 | = | 2 | X |
| 2 | X | = | 30 |
| X | = | 30 | ÷ | 2 |
| = | 30 | × | 1 2 |
| = | 15 | × | 1 |
| X | = | 15 |