| 40 | X | = | ( | 200 | + | 40 | ) | ( | X | − | 10 100 | ) |
| Right side of the equation = | 200 | ( | X | − | 10 100 | ) | + | 40 | ( | X | − | 10 100 | ) |
| = | 200 | X | − | 200 | × | 10 100 | + | 40 | ( | X | − | 10 100 | ) |
| = | 200 | X | − | 20 | + | 40 | ( | X | − | 10 100 | ) |
| = | 200 | X | − | 20 | + | 40 | X | − | 40 | × | 10 100 |
| = | 200 | X | − | 20 | + | 40 | X | − | 4 |
| = | 240 | X | − | 24 |
| 40 | X | = | 240 | X | − | 24 |
| 40 | X | − | 240 | X | = | - | 24 |
| - | 200 | X | = | - | 24 |
| 24 | = | 200 | X |
| 200 | X | = | 24 |
| X | = | 24 | ÷ | 200 |
| = | 24 | × | 1 200 |
| = | 3 | × | 1 25 |
| X | = | 3 25 |
| X | = | 0.12 |