| X | − | ( | 1 | ÷ | 21 | × | X | − | 5 | ) | − | ( | 1 | ÷ | 15 | × | X | − | 3 | ) | = | 206 |
| Left side of the equation = | X | − | 1 | ÷ | 21 | × | X | + | 5 | − | ( | 1 | ÷ | 15 | × | X | − | 3 | ) |
| = | X | − | 1 21 | X | + | 5 | − | ( | 1 | ÷ | 15 | × | X | − | 3 | ) |
| = | 20 21 | X | + | 5 | − | ( | 1 | ÷ | 15 | × | X | − | 3 | ) |
| = | 20 21 | X | + | 5 | − | 1 | ÷ | 15 | × | X | + | 3 |
| = | 20 21 | X | + | 5 | − | 1 15 | X | + | 3 |
| = | 31 35 | X | + | 8 |
31 35 | X | + | 8 | = | 206 |
31 35 | X | = | 206 | − | 8 |
31 35 | X | = | 198 |
| X | = | 198 | ÷ | 31 35 |
| = | 198 | × | 35 31 |
| X | = | 6930 31 |
| X | = | 223.548387 |