( | 400 | − | x | ) | ( | 8 | + | 2 | x | ÷ | 25 | ) | = | 4800 |
方程左边 = | 400 | ( | 8 | + | 2 | x | ÷ | 25 | ) | − | x | ( | 8 | + | 2 | x | ÷ | 25 | ) |
= | 400 | × | 8 | + | 400 | × | 2 | x | ÷ | 25 | − | x | ( | 8 | + | 2 | x | ÷ | 25 | ) |
= | 3200 | + | 32 | x | − | x | ( | 8 | + | 2 | x | ÷ | 25 | ) |
= | 3200 | + | 32 | x | − | x | × | 8 | − | x | × | 2 | x | ÷ | 25 |
= | 3200 | + | 32 | x | − | x | × | 8 | − | x | × | 2 25 | x |
= | 3200 | + | 24 | x | − | x | × | 2 25 | x |
3200 | + | 24 | x | − | x | × | 2 25 | x | = | 4800 |