| ( | 219 100 | − | 3 2 | x | ) | ( | 219 50 | − | x | ) | = | 4113 500000 |
| 方程左边 = | 219 100 | ( | 219 50 | − | x | ) | − | 3 2 | x | ( | 219 50 | − | x | ) |
| = | 219 100 | × | 219 50 | − | 219 100 | x | − | 3 2 | x | ( | 219 50 | − | x | ) |
| = | 47961 5000 | − | 219 100 | x | − | 3 2 | x | ( | 219 50 | − | x | ) |
| = | 47961 5000 | − | 219 100 | x | − | 3 2 | x | × | 219 50 | + | 3 2 | x | x |
| = | 47961 5000 | − | 219 100 | x | − | 657 100 | x | + | 3 2 | x | x |
| = | 47961 5000 | − | 219 25 | x | + | 3 2 | x | x |
47961 5000 | − | 219 25 | x | + | 3 2 | x | x | = | 4113 500000 |