27 500 | X | + | ( | 20 | − | X | ) | × | 207 2500 | = | 153 125 |
| Left side of the equation = | 27 500 | X | + | 20 | × | 207 2500 | − | X | × | 207 2500 |
| = | 27 500 | X | + | 207 125 | − | X | × | 207 2500 |
| = | - | 18 625 | X | + | 207 125 |
| - | 18 625 | X | + | 207 125 | = | 153 125 |
| - | 18 625 | X | = | 153 125 | − | 207 125 |
| - | 18 625 | X | = | - | 54 125 |
54 125 | = | 18 625 | X |
18 625 | X | = | 54 125 |
| X | = | 54 125 | ÷ | 18 625 |
| = | 54 125 | × | 625 18 |
| = | 3 | × | 5 |
| X | = | 15 |