1 | ( | - | 18 | − | 12 | ) | − | a | ( | 6 | a | + | 12 | ) | + | ( | - | 3 | ( | 2 | a | + | 6 | ) | ) | = | 0 |
Left side of the equation = | - | 1 | × | 18 | − | 1 | × | 12 | − | a | ( | 6 | a | + | 12 | ) | + | ( | - | 3 | ( | 2 | a | + | 6 | ) | ) |
= | - | 18 | − | 12 | − | a | ( | 6 | a | + | 12 | ) | + | ( | - | 3 | ( | 2 | a | + | 6 | ) | ) |
= | - | 30 | − | a | ( | 6 | a | + | 12 | ) | + | ( | - | 3 | ( | 2 | a | + | 6 | ) | ) |
= | - | 30 | − | a | × | 6 | a | − | a | × | 12 | + | ( | - | 3 | ( | 2 | a | + | 6 | ) | ) |
= | - | 30 | − | a | × | 6 | a | − | 12 | a | − | 3 | ( | 2 | a | + | 6 | ) |
= | - | 30 | − | a | × | 6 | a | − | 12 | a | − | 3 | × | 2 | a | − | 3 | × | 6 |
= | - | 30 | − | a | × | 6 | a | − | 12 | a | − | 6 | a | − | 18 |
= | - | 48 | − | a | × | 6 | a | − | 18 | a |
- | 48 | − | a | × | 6 | a | − | 18 | a | = | 0 |