80 | x | + | 200 | ( | 520 | − | x | ) | = | 50000 |
方程左边 = | 80 | x | + | 200 | × | 520 | − | 200 | x |
= | 80 | x | + | 104000 | − | 200 | x |
= | - | 120 | x | + | 104000 |
- | 120 | x | + | 104000 | = | 50000 |
- | 120 | x | = | 50000 | − | 104000 |
- | 120 | x | = | - | 54000 |
54000 | = | 120 | x |
120 | x | = | 54000 |
x | = | 54000 | ÷ | 120 |
= | 54000 | × | 1 120 |
= | 450 | × | 1 |
x | = | 450 |