| ( | X | ( | 20 | − | 10 | ) | − | 8000 | ) | ÷ | ( | 10 | X | + | 8000 | ) | = | 20 100 |
| Multiply both sides of the equation by: | ( | 10 | X | + | 8000 | ) |
| ( | X | ( | 20 | − | 10 | ) | − | 8000 | ) | = | 20 100 | ( | 10 | X | + | 8000 | ) |
| X | ( | 20 | − | 10 | ) | − | 8000 | = | 20 100 | ( | 10 | X | + | 8000 | ) |
| X | ( | 20 | − | 10 | ) | − | 8000 | = | 20 100 | × | 10 | X | + | 20 100 | × | 8000 |
| X | ( | 20 | − | 10 | ) | − | 8000 | = | 2 | X | + | 1600 |
| X | × | 20 | − | X | × | 10 | − | 8000 | = | 2 | X | + | 1600 |
| 10 | X | − | 8000 | = | 2 | X | + | 1600 |
| 10 | X | − | 2 | X | = | 1600 | + | 8000 |
| 8 | X | = | 1600 | + | 8000 |
| 8 | X | = | 9600 |
| X | = | 9600 | ÷ | 8 |
| = | 9600 | × | 1 8 |
| = | 1200 | × | 1 |
| X | = | 1200 |