| ( | 45 | + | 3 5 | a | ) | ( | 150 | − | 3 | a | ) | = | 4500 |
| Left side of the equation = | 45 | ( | 150 | − | 3 | a | ) | + | 3 5 | a | ( | 150 | − | 3 | a | ) |
| = | 45 | × | 150 | − | 45 | × | 3 | a | + | 3 5 | a | ( | 150 | − | 3 | a | ) |
| = | 6750 | − | 135 | a | + | 3 5 | a | ( | 150 | − | 3 | a | ) |
| = | 6750 | − | 135 | a | + | 3 5 | a | × | 150 | − | 3 5 | a | × | 3 | a |
| = | 6750 | − | 135 | a | + | 90 | a | − | 9 5 | a | a |
| = | 6750 | − | 45 | a | − | 9 5 | a | a |
| 6750 | − | 45 | a | − | 9 5 | a | a | = | 4500 |