| 1000 | ( | X | − | 180 | ) | = | 1500 | ( | X | − | 500 | ) |
| Left side of the equation = | 1000 | X | − | 1000 | × | 180 |
| = | 1000 | X | − | 180000 |
| 1000 | X | − | 180000 | = | 1500 | ( | X | − | 500 | ) |
| Right side of the equation = | 1500 | X | − | 1500 | × | 500 |
| = | 1500 | X | − | 750000 |
| 1000 | X | − | 180000 | = | 1500 | X | − | 750000 |
| 1000 | X | − | 1500 | X | = | - | 750000 | + | 180000 |
| - | 500 | X | = | - | 750000 | + | 180000 |
| - | 500 | X | = | - | 570000 |
| 570000 | = | 500 | X |
| 500 | X | = | 570000 |
| X | = | 570000 | ÷ | 500 |
| = | 570000 | × | 1 500 |
| = | 1140 | × | 1 |
| X | = | 1140 |