| ( | 3 5 | − | x | ) | ( | 3 10 | − | x | ) | = | 1 2 | × | 1 10 |
| 方程左边 = | 3 5 | ( | 3 10 | − | x | ) | − | x | ( | 3 10 | − | x | ) |
| = | 3 5 | × | 3 10 | − | 3 5 | x | − | x | ( | 3 10 | − | x | ) |
| = | 9 50 | − | 3 5 | x | − | x | ( | 3 10 | − | x | ) |
| = | 9 50 | − | 3 5 | x | − | x | × | 3 10 | + | x | x |
| = | 9 50 | − | 9 10 | x | + | x | x |
9 50 | − | 9 10 | x | + | x | x | = | 1 2 | × | 1 10 |
| 方程右边 = | 1 20 |
9 50 | − | 9 10 | x | + | x | x | = | 1 20 |