( | 20 | − | 2 | x | ) | ( | 8 | − | 2 | x | ) | − | x | ( | 8 | − | 2 | x | ) | = | 56 |
方程左边 = | 20 | ( | 8 | − | 2 | x | ) | − | 2 | x | ( | 8 | − | 2 | x | ) | − | x | ( | 8 | − | 2 | x | ) |
= | 20 | × | 8 | − | 20 | × | 2 | x | − | 2 | x | ( | 8 | − | 2 | x | ) | − | x | ( | 8 | − | 2 | x | ) |
= | 160 | − | 40 | x | − | 2 | x | ( | 8 | − | 2 | x | ) | − | x | ( | 8 | − | 2 | x | ) |
= | 160 | − | 40 | x | − | 2 | x | × | 8 | + | 2 | x | × | 2 | x | − | x | ( | 8 | − | 2 | x | ) |
= | 160 | − | 40 | x | − | 16 | x | + | 4 | x | x | − | x | ( | 8 | − | 2 | x | ) |
= | 160 | − | 56 | x | + | 4 | x | x | − | x | ( | 8 | − | 2 | x | ) |
= | 160 | − | 56 | x | + | 4 | x | x | − | x | × | 8 | + | x | × | 2 | x |
= | 160 | − | 64 | x | + | 4 | x | x | + | x | × | 2 | x |
160 | − | 64 | x | + | 4 | x | x | + | x | × | 2 | x | = | 56 |
x2= | 26 3 |