( | 2 | x | ) | ( | 2 | x | ) | + | ( | 6 | − | x | ) | ( | 6 | − | x | ) | = | 45 |
方程左边 = | 2 | x | ( | 2 | x | ) | + | ( | 6 | − | x | ) | ( | 6 | − | x | ) |
= | 2 | x | × | 2 | x | + | ( | 6 | − | x | ) | ( | 6 | − | x | ) |
= | 4 | x | x | + | ( | 6 | − | x | ) | ( | 6 | − | x | ) |
= | 4 | x | x | + | 6 | ( | 6 | − | x | ) | − | x | ( | 6 | − | x | ) |
= | 4 | x | x | + | 6 | × | 6 | − | 6 | x | − | x | ( | 6 | − | x | ) |
= | 4 | x | x | + | 36 | − | 6 | x | − | x | ( | 6 | − | x | ) |
= | 4 | x | x | + | 36 | − | 6 | x | − | x | × | 6 | + | x | x |
= | 4 | x | x | + | 36 | − | 12 | x | + | x | x |
4 | x | x | + | 36 | − | 12 | x | + | x | x | = | 45 |
x1= | - | 3 5 |
x2=3 |