( | x | − | 100 | ) | ( | 1000 | − | 2 | x | ) | − | 40000 | = | 32800 |
方程左边 = | x | ( | 1000 | − | 2 | x | ) | − | 100 | ( | 1000 | − | 2 | x | ) | − | 40000 |
= | x | × | 1000 | − | x | × | 2 | x | − | 100 | ( | 1000 | − | 2 | x | ) | − | 40000 |
= | 1000 | x | − | x | × | 2 | x | − | 100 | × | 1000 | + | 100 | × | 2 | x | − | 40000 |
= | 1000 | x | − | x | × | 2 | x | − | 100000 | + | 200 | x | − | 40000 |
= | 1200 | x | − | x | × | 2 | x | − | 140000 |
1200 | x | − | x | × | 2 | x | − | 140000 | = | 32800 |