( | 100 | + | 200 | x | ) | ( | 2 | − | x | ) | = | 300 |
方程左边 = | 100 | ( | 2 | − | x | ) | + | 200 | x | ( | 2 | − | x | ) |
= | 100 | × | 2 | − | 100 | x | + | 200 | x | ( | 2 | − | x | ) |
= | 200 | − | 100 | x | + | 200 | x | ( | 2 | − | x | ) |
= | 200 | − | 100 | x | + | 200 | x | × | 2 | − | 200 | x | x |
= | 200 | − | 100 | x | + | 400 | x | − | 200 | x | x |
= | 200 | + | 300 | x | − | 200 | x | x |
200 | + | 300 | x | − | 200 | x | x | = | 300 |
x1= | 1 2 |
x2=1 |