| ( | 5 | a | + | 256 | ) | ( | 15 | − | a | ) | = | 4250 |
| Left side of the equation = | 5 | a | ( | 15 | − | a | ) | + | 256 | ( | 15 | − | a | ) |
| = | 5 | a | × | 15 | − | 5 | a | a | + | 256 | ( | 15 | − | a | ) |
| = | 75 | a | − | 5 | a | a | + | 256 | ( | 15 | − | a | ) |
| = | 75 | a | − | 5 | a | a | + | 256 | × | 15 | − | 256 | a |
| = | 75 | a | − | 5 | a | a | + | 3840 | − | 256 | a |
| = | - | 181 | a | − | 5 | a | a | + | 3840 |
| - | 181 | a | − | 5 | a | a | + | 3840 | = | 4250 |