( | 100 | + | x | ) | ( | 1000 | − | 2 | x | ) | = | 115200 |
方程左边 = | 100 | ( | 1000 | − | 2 | x | ) | + | x | ( | 1000 | − | 2 | x | ) |
= | 100 | × | 1000 | − | 100 | × | 2 | x | + | x | ( | 1000 | − | 2 | x | ) |
= | 100000 | − | 200 | x | + | x | ( | 1000 | − | 2 | x | ) |
= | 100000 | − | 200 | x | + | x | × | 1000 | − | x | × | 2 | x |
= | 100000 | + | 800 | x | − | x | × | 2 | x |
100000 | + | 800 | x | − | x | × | 2 | x | = | 115200 |