( | x | + | 3 | ) | ( | x | + | 1 | ) | ( | x | − | 3 | ) | = | 0 |
方程左边 = | x | ( | x | + | 1 | ) | ( | x | − | 3 | ) | + | 3 | ( | x | + | 1 | ) | ( | x | − | 3 | ) |
= | x | x | ( | x | − | 3 | ) | + | x | × | 1 | ( | x | − | 3 | ) | + | 3 | ( | x | + | 1 | ) | ( | x | − | 3 | ) |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | ( | x | − | 3 | ) | + | 3 | ( | x | + | 1 | ) | ( | x | − | 3 | ) |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | x | × | 1 | × | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | x | × | 3 | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 3 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 3 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 3 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 3 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 12 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 12 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 12 | x | + | 3 |
= | x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 9 | x | + | 3 |
x | x | x | − | x | x | × | 3 | + | x | × | 1 | x | − | 9 | x | + | 3 | = | 0 |