| ( | ( | 10000 | + | 5500 | x | ) | × | 4 25 | x | − | 1000 | ) | × | 5 | x | = | 10000 |
| 方程左边 = | ( | 10000 | + | 5500 | x | ) | × | 4 25 | x | × | 5 | x | − | 1000 | × | 5 | x |
| = | ( | 10000 | + | 5500 | x | ) | × | 4 5 | x | x | − | 5000 | x |
| = | 10000 | × | 4 5 | x | x | + | 5500 | x | × | 4 5 | x | x | − | 5000 | x |
| = | 8000 | x | x | + | 4400 | x | x | x | − | 5000 | x |
| 8000 | x | x | + | 4400 | x | x | x | − | 5000 | x | = | 10000 |