| - | 18 | = | ( | x | − | 45 4 | ) | ÷ | 45 4 | × | 100 |
| Right side of the equation = | ( | x | − | 45 4 | ) | × | 80 9 |
| - | 18 | = | ( | x | − | 45 4 | ) | × | 80 9 |
| Right side of the equation = | x | × | 80 9 | − | 45 4 | × | 80 9 |
| = | x | × | 80 9 | − | 100 |
| - | 18 | = | 80 9 | x | − | 100 |
| - | 80 9 | x | = | - | 100 | + | 18 |
| - | 80 9 | x | = | - | 82 |
| 82 | = | 80 9 | x |
80 9 | x | = | 82 |
| x | = | 82 | ÷ | 80 9 |
| = | 82 | × | 9 80 |
| = | 41 | × | 9 40 |
| x | = | 369 40 |
| x | = | 9.225 |