| 5 | x | ( | x | − | 3 | ) | = | ( | x | + | 1 | ) | ( | x | − | 3 | ) |
| 方程左边 = | 5 | x | x | − | 5 | x | × | 3 |
| = | 5 | x | x | − | 15 | x |
| 5 | x | x | − | 15 | x | = | ( | x | + | 1 | ) | ( | x | − | 3 | ) |
| 方程右边 = | x | ( | x | − | 3 | ) | + | 1 | ( | x | − | 3 | ) |
| = | x | x | − | x | × | 3 | + | 1 | ( | x | − | 3 | ) |
| = | x | x | − | 3 | x | + | 1 | x | − | 1 | × | 3 |
| = | x | x | − | 3 | x | + | 1 | x | − | 3 |
| = | x | x | − | 2 | x | − | 3 |
| 5 | x | x | − | 15 | x | = | x | x | − | 2 | x | − | 3 |
| x1= | 1 4 |
| x2=3 |