( | x | − | 3 | ( | 500 | − | ( | x | − | 4 | ) | ÷ | 1 10 | × | x | × | 10 | ) | ) | = | 800 |
方程左边 = | x | − | 3 | ( | 500 | − | ( | x | − | 4 | ) | ÷ | 1 10 | × | x | × | 10 | ) |
= | x | − | 3 | × | 500 | + | 3 | ( | x | − | 4 | ) | ÷ | 1 10 | × | x | × | 10 |
= | x | − | 1500 | + | 300 | ( | x | − | 4 | ) | x |
= | x | − | 1500 | + | 300 | x | x | − | 300 | × | 4 | x |
= | x | − | 1500 | + | 300 | x | x | − | 1200 | x |
= | - | 1199 | x | − | 1500 | + | 300 | x | x |
- | 1199 | x | − | 1500 | + | 300 | x | x | = | 800 |