| X | − | ( | X | × | 1 10 | ) | − | ( | X | × | 1 5 | ) | − | 7 | = | 798 |
| Left side of the equation = | X | − | X | × | 1 10 | − | ( | X | × | 1 5 | ) | − | 7 |
| = | 9 10 | X | − | ( | X | × | 1 5 | ) | − | 7 |
| = | 9 10 | X | − | X | × | 1 5 | − | 7 |
| = | 7 10 | X | − | 7 |
7 10 | X | − | 7 | = | 798 |
7 10 | X | = | 798 | + | 7 |
7 10 | X | = | 805 |
| X | = | 805 | ÷ | 7 10 |
| = | 805 | × | 10 7 |
| = | 115 | × | 10 |
| X | = | 1150 |