| ( | X | − | 3 | ) | × | 40 100 | + | 18 | = | X |
| Left side of the equation = | X | × | 40 100 | − | 3 | × | 40 100 | + | 18 |
| = | X | × | 40 100 | − | 6 5 | + | 18 |
| = | 40 100 | X | + | 84 5 |
40 100 | X | + | 84 5 | = | X |
40 100 | X | − | X | = | - | 84 5 |
| - | 3 5 | X | = | - | 84 5 |
84 5 | = | 3 5 | X |
3 5 | X | = | 84 5 |
| X | = | 84 5 | ÷ | 3 5 |
| = | 84 5 | × | 5 3 |
| = | 28 | × | 1 |
| X | = | 28 |