| 20 | × | 80 | + | 20 | × | 3 4 | ( | X | − | 1 5 | X | − | 80 | − | 8 | X | ) | = | 1772 |
| Left side of the equation = | 1600 | + | 15 | ( | X | − | 1 5 | X | − | 80 | − | 8 | X | ) |
| 1600 | + | 15 | ( | X | − | 1 5 | X | − | 80 | − | 8 | X | ) | = | 1772 |
| Left side of the equation = | 1600 | + | 15 | X | − | 15 | × | 1 5 | X | − | 15 | × | 80 | − | 15 | × | 8 | X |
| = | 1600 | + | 15 | X | − | 3 | X | − | 1200 | − | 120 | X |
| = | 400 | − | 108 | X |
| 400 | − | 108 | X | = | 1772 |
| - | 108 | X | = | 1772 | − | 400 |
| - | 108 | X | = | 1372 |
| - | 1372 | = | 108 | X |
| 108 | X | = | - | 1372 |
| X | = | - | 1372 | ÷ | 108 |
| = | - | 1372 | × | 1 108 |
| = | - | 343 | × | 1 27 |
| X | = | - | 343 27 |
| X | = | - 12.703704 |