( | x | − | 4 | ) | ( | x | − | 4 | ) | + | ( | x | − | 2 | ) | ( | x | − | 2 | ) | = | x | x |
方程左边 = | x | ( | x | − | 4 | ) | − | 4 | ( | x | − | 4 | ) | + | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
= | x | x | − | x | × | 4 | − | 4 | ( | x | − | 4 | ) | + | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
= | x | x | − | 4 | x | − | 4 | x | + | 4 | × | 4 | + | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
= | x | x | − | 4 | x | − | 4 | x | + | 16 | + | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
= | x | x | − | 8 | x | + | 16 | + | ( | x | − | 2 | ) | ( | x | − | 2 | ) |
= | x | x | − | 8 | x | + | 16 | + | x | ( | x | − | 2 | ) | − | 2 | ( | x | − | 2 | ) |
= | x | x | − | 8 | x | + | 16 | + | x | x | − | x | × | 2 | − | 2 | ( | x | − | 2 | ) |
= | x | x | − | 10 | x | + | 16 | + | x | x | − | 2 | ( | x | − | 2 | ) |
= | x | x | − | 10 | x | + | 16 | + | x | x | − | 2 | x | + | 2 | × | 2 |
= | x | x | − | 10 | x | + | 16 | + | x | x | − | 2 | x | + | 4 |
= | x | x | − | 12 | x | + | 20 | + | x | x |
x | x | − | 12 | x | + | 20 | + | x | x | = | x | x |