| 15 | x | − | 15 | ( | x | + | 1 | ) | × | 9 10 | = | 45 |
| Left side of the equation = | 15 | x | − | 27 2 | ( | x | + | 1 | ) |
| 15 | x | − | 27 2 | ( | x | + | 1 | ) | = | 45 |
| Left side of the equation = | 15 | x | − | 27 2 | x | − | 27 2 | × | 1 |
| = | 15 | x | − | 27 2 | x | − | 27 2 |
| = | 3 2 | x | − | 27 2 |
3 2 | x | − | 27 2 | = | 45 |
3 2 | x | = | 45 | + | 27 2 |
3 2 | x | = | 117 2 |
| x | = | 117 2 | ÷ | 3 2 |
| = | 117 2 | × | 2 3 |
| = | 39 | × | 1 |
| x | = | 39 |