| x | − | ( | 1 | ÷ | 8 | × | x | + | 21 | ) | − | ( | 1 | ÷ | 6 | × | x | − | 6 | ) | = | 172 |
| Left side of the equation = | x | − | 1 | ÷ | 8 | × | x | − | 21 | − | ( | 1 | ÷ | 6 | × | x | − | 6 | ) |
| = | x | − | 1 8 | x | − | 21 | − | ( | 1 | ÷ | 6 | × | x | − | 6 | ) |
| = | 7 8 | x | − | 21 | − | ( | 1 | ÷ | 6 | × | x | − | 6 | ) |
| = | 7 8 | x | − | 21 | − | 1 | ÷ | 6 | × | x | + | 6 |
| = | 7 8 | x | − | 21 | − | 1 6 | x | + | 6 |
| = | 17 24 | x | − | 15 |
17 24 | x | − | 15 | = | 172 |
17 24 | x | = | 172 | + | 15 |
17 24 | x | = | 187 |
| x | = | 187 | ÷ | 17 24 |
| = | 187 | × | 24 17 |
| = | 11 | × | 24 |
| x | = | 264 |