| ( | 1 | + | 20 100 | ) | × | 10 | X | = | 15 | ( | X | − | 3 | ) |
| Left side of the equation = | 1 | × | 10 | X | + | 20 100 | × | 10 | X |
| = | 10 | X | + | 2 | X |
| = | 12 | X |
| 12 | X | = | 15 | ( | X | − | 3 | ) |
| Right side of the equation = | 15 | X | − | 15 | × | 3 |
| = | 15 | X | − | 45 |
| 12 | X | = | 15 | X | − | 45 |
| 12 | X | − | 15 | X | = | - | 45 |
| - | 3 | X | = | - | 45 |
| 45 | = | 3 | X |
| 3 | X | = | 45 |
| X | = | 45 | ÷ | 3 |
| = | 45 | × | 1 3 |
| = | 15 | × | 1 |
| X | = | 15 |