| ( | 1 10 | − | x | ) | ( | 1 2 | − | 2 | x | ) | = | 3 2500000000000 |
| 方程左边 = | 1 10 | ( | 1 2 | − | 2 | x | ) | − | x | ( | 1 2 | − | 2 | x | ) |
| = | 1 10 | × | 1 2 | − | 1 10 | × | 2 | x | − | x | ( | 1 2 | − | 2 | x | ) |
| = | 1 20 | − | 1 5 | x | − | x | ( | 1 2 | − | 2 | x | ) |
| = | 1 20 | − | 1 5 | x | − | x | × | 1 2 | + | x | × | 2 | x |
| = | 1 20 | − | 7 10 | x | + | x | × | 2 | x |
1 20 | − | 7 10 | x | + | x | × | 2 | x | = | 3 2500000000000 |
| x1= | 1 10 |
| x2= | 1 4 |