| 28 | x | − | 17 | ( | x | + | 38 | ) | = | 20 | x | − | 880 |
| Left side of the equation = | 28 | x | − | 17 | x | − | 17 | × | 38 |
| = | 28 | x | − | 17 | x | − | 646 |
| = | 11 | x | − | 646 |
| 11 | x | − | 646 | = | 20 | x | − | 880 |
| 11 | x | − | 20 | x | = | - | 880 | + | 646 |
| - | 9 | x | = | - | 880 | + | 646 |
| - | 9 | x | = | - | 234 |
| 234 | = | 9 | x |
| 9 | x | = | 234 |
| x | = | 234 | ÷ | 9 |
| = | 234 | × | 1 9 |
| = | 26 | × | 1 |
| x | = | 26 |