| ( | X | − | 800 | ) | × | 1 5 | = | X | − | 2500 |
| Left side of the equation = | X | × | 1 5 | − | 800 | × | 1 5 |
| = | X | × | 1 5 | − | 160 |
1 5 | X | − | 160 | = | X | − | 2500 |
1 5 | X | − | X | = | - | 2500 | + | 160 |
| - | 4 5 | X | = | - | 2500 | + | 160 |
| - | 4 5 | X | = | - | 2340 |
| 2340 | = | 4 5 | X |
4 5 | X | = | 2340 |
| X | = | 2340 | ÷ | 4 5 |
| = | 2340 | × | 5 4 |
| = | 585 | × | 5 |
| X | = | 2925 |