28 500 | x | + | ( | ( | 5000 | − | x | ) | × | 31 500 | ) | = | 1478 5 |
| 方程左边 = | 28 500 | x | + | ( | 5000 | − | x | ) | × | 31 500 |
| = | 28 500 | x | + | 5000 | × | 31 500 | − | x | × | 31 500 |
| = | 28 500 | x | + | 310 | − | x | × | 31 500 |
| = | - | 3 500 | x | + | 310 |
| - | 3 500 | x | + | 310 | = | 1478 5 |
| - | 3 500 | x | = | 1478 5 | − | 310 |
| - | 3 500 | x | = | - | 72 5 |
72 5 | = | 3 500 | x |
3 500 | x | = | 72 5 |
| x | = | 72 5 | ÷ | 3 500 |
| = | 72 5 | × | 500 3 |
| = | 24 | × | 100 |
| x | = | 2400 |