a | ( | a | − | 1 | ) | ( | a | + | 2 | ) | ( | a | + | 3 | ) | = | 0 |
方程左边 = | a | a | ( | a | + | 2 | ) | ( | a | + | 3 | ) | − | a | × | 1 | ( | a | + | 2 | ) | ( | a | + | 3 | ) |
= | a | a | a | ( | a | + | 3 | ) | + | a | a | × | 2 | ( | a | + | 3 | ) | − | a | × | 1 | ( | a | + | 2 | ) | ( | a | + | 3 | ) |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | ( | a | + | 3 | ) |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
= | a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a |
a | a | a | a | + | a | a | a | × | 3 | + | a | a | × | 2 | a | = | 0 |