| 440 | = | 40 | × | 24 | − | x | x | − | ( | 24 | − | x | ) | ( | 40 | − | x | ) |
| 方程右边 = | 960 | − | x | x | − | ( | 24 | − | x | ) | ( | 40 | − | x | ) |
| 440 | = | 960 | − | x | x | − | ( | 24 | − | x | ) | ( | 40 | − | x | ) |
| 方程右边 = | 960 | − | x | x | − | 24 | ( | 40 | − | x | ) | + | x | ( | 40 | − | x | ) |
| = | 960 | − | x | x | − | 24 | × | 40 | + | 24 | x | + | x | ( | 40 | − | x | ) |
| = | 960 | − | x | x | − | 960 | + | 24 | x | + | x | ( | 40 | − | x | ) |
| = | 0 | − | x | x | + | 24 | x | + | x | ( | 40 | − | x | ) |
| = | 0 | − | x | x | + | 24 | x | + | x | × | 40 | − | x | x |
| = | 0 | − | x | x | + | 64 | x | − | x | x |
| 440 | = | 0 | − | x | x | + | 64 | x | − | x | x |