( | 12 | − | 3 | x | ) | ( | 16 | − | 9 | x | ) | = | 32 |
方程左边 = | 12 | ( | 16 | − | 9 | x | ) | − | 3 | x | ( | 16 | − | 9 | x | ) |
= | 12 | × | 16 | − | 12 | × | 9 | x | − | 3 | x | ( | 16 | − | 9 | x | ) |
= | 192 | − | 108 | x | − | 3 | x | ( | 16 | − | 9 | x | ) |
= | 192 | − | 108 | x | − | 3 | x | × | 16 | + | 3 | x | × | 9 | x |
= | 192 | − | 108 | x | − | 48 | x | + | 27 | x | x |
= | 192 | − | 156 | x | + | 27 | x | x |
192 | − | 156 | x | + | 27 | x | x | = | 32 |
x1= | 4 3 |
x2= | 40 9 |