| 9 | ( | x | + | 2 | ) | ( | x | + | 2 | ) | = | 16 | ( | 2 | x | − | 5 | ) | ( | 2 | x | − | 5 | ) |
| 方程左边 = | 9 | x | ( | x | + | 2 | ) | + | 9 | × | 2 | ( | x | + | 2 | ) |
| = | 9 | x | ( | x | + | 2 | ) | + | 18 | ( | x | + | 2 | ) |
| = | 9 | x | x | + | 9 | x | × | 2 | + | 18 | ( | x | + | 2 | ) |
| = | 9 | x | x | + | 18 | x | + | 18 | ( | x | + | 2 | ) |
| = | 9 | x | x | + | 18 | x | + | 18 | x | + | 18 | × | 2 |
| = | 9 | x | x | + | 18 | x | + | 18 | x | + | 36 |
| = | 9 | x | x | + | 36 | x | + | 36 |
| 9 | x | x | + | 36 | x | + | 36 | = | 16 | ( | 2 | x | − | 5 | ) | ( | 2 | x | − | 5 | ) |
| 方程右边 = | 16 | × | 2 | x | ( | 2 | x | − | 5 | ) | − | 16 | × | 5 | ( | 2 | x | − | 5 | ) |
| = | 32 | x | ( | 2 | x | − | 5 | ) | − | 80 | ( | 2 | x | − | 5 | ) |
| = | 32 | x | × | 2 | x | − | 32 | x | × | 5 | − | 80 | ( | 2 | x | − | 5 | ) |
| = | 64 | x | x | − | 160 | x | − | 80 | ( | 2 | x | − | 5 | ) |
| = | 64 | x | x | − | 160 | x | − | 80 | × | 2 | x | + | 80 | × | 5 |
| = | 64 | x | x | − | 160 | x | − | 160 | x | + | 400 |
| = | 64 | x | x | − | 320 | x | + | 400 |
| 9 | x | x | + | 36 | x | + | 36 | = | 64 | x | x | − | 320 | x | + | 400 |
| x1= | 14 11 |
| x2= | 26 5 |