x | ( | 500 | − | x | ) | ( | 640 | − | x | ) | = | 50000 | ÷ | 29 20 |
方程左边 = | x | × | 500 | ( | 640 | − | x | ) | − | x | x | ( | 640 | − | x | ) |
= | x | × | 500 | × | 640 | − | x | × | 500 | x | − | x | x | ( | 640 | − | x | ) |
= | x | × | 320000 | − | x | × | 500 | x | − | x | x | ( | 640 | − | x | ) |
= | 320000 | x | − | x | × | 500 | x | − | x | x | × | 640 | + | x | x | x |
320000 | x | − | x | × | 500 | x | − | x | x | × | 640 | + | x | x | x | = | 50000 | ÷ | 29 20 |
方程右边 = | 1000000 29 |
320000 | x | − | x | × | 500 | x | − | x | x | × | 640 | + | x | x | x | = | 1000000 29 |