| - | 3 | × | 6 | ( | a | + | 1 | ) | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) | = | 0 |
| 方程左边 = | - | 18 | ( | a | + | 1 | ) | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| - | 18 | ( | a | + | 1 | ) | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) | = | 0 |
| 方程左边 = | - | 18 | a | ( | a | + | 1 | ) | − | 18 | × | 1 | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | ( | a | + | 1 | ) | − | 18 | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 18 | a | × | 1 | − | 18 | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 18 | a | − | 18 | ( | a | + | 1 | ) | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 18 | a | − | 18 | a | − | 18 | × | 1 | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 18 | a | − | 18 | a | − | 18 | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 36 | a | − | 18 | − | ( | 2 | − | 3 | a | ) | × | 12 | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 36 | a | − | 18 | − | 2 | × | 12 | ( | a | + | 1 | ) | + | 3 | a | × | 12 |
| = | - | 18 | a | a | − | 36 | a | − | 18 | − | 24 | ( | a | + | 1 | ) | + | 36 | a | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 36 | a | − | 18 | − | 24 | a | − | 24 | × | 1 | + | 36 | a |
| = | - | 18 | a | a | − | 36 | a | − | 18 | − | 24 | a | − | 24 | + | 36 | a | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 60 | a | − | 42 | + | 36 | a | ( | a | + | 1 | ) |
| = | - | 18 | a | a | − | 60 | a | − | 42 | + | 36 | a | a | + | 36 | a | × | 1 |
| = | - | 18 | a | a | − | 60 | a | − | 42 | + | 36 | a | a | + | 36 | a |
| = | - | 18 | a | a | − | 24 | a | − | 42 | + | 36 | a | a |
| - | 18 | a | a | − | 24 | a | − | 42 | + | 36 | a | a | = | 0 |
| a2= | 7 3 |