| ( | 1 | − | x | ) | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) | = | 3 1000 |
| 方程左边 = | 1 | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 1 | × | 9 10 | ( | 4 5 | − | x | ) | − | 1 | x | ( | 4 5 | − | x | ) | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 9 10 | ( | 4 5 | − | x | ) | − | 1 | x | ( | 4 5 | − | x | ) | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 9 10 | × | 4 5 | − | 9 10 | x | − | 1 | x | ( | 4 5 | − | x | ) | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 9 10 | x | − | 1 | x | ( | 4 5 | − | x | ) | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 9 10 | x | − | 1 | x | × | 4 5 | + | 1 | x | x | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 9 10 | x | − | 4 5 | x | + | 1 | x | x | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 17 10 | x | + | 1 | x | x | − | x | ( | 9 10 | − | x | ) | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 17 10 | x | + | 1 | x | x | − | x | × | 9 10 | ( | 4 5 | − | x | ) | + | x | x | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 17 10 | x | + | 1 | x | x | − | x | × | 9 10 | × | 4 5 | + | x | × | 9 10 | x |
| = | 18 25 | − | 17 10 | x | + | 1 | x | x | − | x | × | 18 25 | + | x | × | 9 10 | x | + | x |
| = | 18 25 | − | 121 50 | x | + | 1 | x | x | + | x | × | 9 10 | x | + | x | x | ( | 4 5 | − | x | ) |
| = | 18 25 | − | 121 50 | x | + | 1 | x | x | + | x | × | 9 10 | x | + | x | x | × | 4 5 |
18 25 | − | 121 50 | x | + | 1 | x | x | + | x | × | 9 10 | x | + | x | x | × | 4 5 | = | 3 1000 |