| ( | 2 | x | + | 3 5 | ) | ( | x | − | 2 5 | ) | = | 39 25 |
| 方程左边 = | 2 | x | ( | x | − | 2 5 | ) | + | 3 5 | ( | x | − | 2 5 | ) |
| = | 2 | x | x | − | 2 | x | × | 2 5 | + | 3 5 | ( | x | − | 2 5 | ) |
| = | 2 | x | x | − | 4 5 | x | + | 3 5 | ( | x | − | 2 5 | ) |
| = | 2 | x | x | − | 4 5 | x | + | 3 5 | x | − | 3 5 | × | 2 5 |
| = | 2 | x | x | − | 4 5 | x | + | 3 5 | x | − | 6 25 |
| = | 2 | x | x | − | 1 5 | x | − | 6 25 |
| 2 | x | x | − | 1 5 | x | − | 6 25 | = | 39 25 |
| x1= | - | 9 10 |
| x2=1 |