| 18 | ( | x | − | 1 | ) | − | 18 | × | 9 10 | = | 36 |
| Left side of the equation = | 18 | ( | x | − | 1 | ) | − | 81 5 |
| 18 | ( | x | − | 1 | ) | − | 81 5 | = | 36 |
| Left side of the equation = | 18 | x | − | 18 | × | 1 | − | 81 5 |
| = | 18 | x | − | 18 | − | 81 5 |
| = | 18 | x | − | 171 5 |
| 18 | x | − | 171 5 | = | 36 |
| 18 | x | = | 36 | + | 171 5 |
| 18 | x | = | 351 5 |
| x | = | 351 5 | ÷ | 18 |
| = | 351 5 | × | 1 18 |
| = | 39 5 | × | 1 2 |
| x | = | 39 10 |
| x | = | 3.9 |