| ( | 5 | X | + | 50 | ) | ( | 20 | − | X | ) | = | 1105 |
| Left side of the equation = | 5 | X | ( | 20 | − | X | ) | + | 50 | ( | 20 | − | X | ) |
| = | 5 | X | × | 20 | − | 5 | X | X | + | 50 | ( | 20 | − | X | ) |
| = | 100 | X | − | 5 | X | X | + | 50 | ( | 20 | − | X | ) |
| = | 100 | X | − | 5 | X | X | + | 50 | × | 20 | − | 50 | X |
| = | 100 | X | − | 5 | X | X | + | 1000 | − | 50 | X |
| = | 50 | X | − | 5 | X | X | + | 1000 |
| 50 | X | − | 5 | X | X | + | 1000 | = | 1105 |