| x | ( | x | − | 1 | ) | + | ( | 36 | − | x | ) | ( | 35 | − | x | ) | = | 630 |
| 方程左边 = | x | x | − | x | × | 1 | + | ( | 36 | − | x | ) | ( | 35 | − | x | ) |
| = | x | x | − | 1 | x | + | 36 | ( | 35 | − | x | ) | − | x | ( | 35 | − | x | ) |
| = | x | x | − | 1 | x | + | 36 | × | 35 | − | 36 | x | − | x | ( | 35 | − | x | ) |
| = | x | x | − | 1 | x | + | 1260 | − | 36 | x | − | x | ( | 35 | − | x | ) |
| = | x | x | − | 37 | x | + | 1260 | − | x | ( | 35 | − | x | ) |
| = | x | x | − | 37 | x | + | 1260 | − | x | × | 35 | + | x | x |
| = | x | x | − | 72 | x | + | 1260 | + | x | x |
| x | x | − | 72 | x | + | 1260 | + | x | x | = | 630 |