| 24 | ( | 18 | X | + | 500 | ) | − | 400 | = | 54 | X |
| Left side of the equation = | 24 | × | 18 | X | + | 24 | × | 500 | − | 400 |
| = | 432 | X | + | 12000 | − | 400 |
| = | 432 | X | + | 11600 |
| 432 | X | + | 11600 | = | 54 | X |
| 432 | X | − | 54 | X | = | - | 11600 |
| 378 | X | = | - | 11600 |
| X | = | - | 11600 | ÷ | 378 |
| = | - | 11600 | × | 1 378 |
| = | - | 5800 | × | 1 189 |
| X | = | - | 5800 189 |
| X | = | - 30.687831 |