8 5 | ( | 1 | + | x | ) | ( | 1 | + | x | ) | = | 5 2 |
| 方程左边 = | 8 5 | × | 1 | ( | 1 | + | x | ) | + | 8 5 | x | ( | 1 | + | x | ) |
| = | 8 5 | ( | 1 | + | x | ) | + | 8 5 | x | ( | 1 | + | x | ) |
| = | 8 5 | × | 1 | + | 8 5 | x | + | 8 5 | x | ( | 1 | + | x | ) |
| = | 8 5 | + | 8 5 | x | + | 8 5 | x | ( | 1 | + | x | ) |
| = | 8 5 | + | 8 5 | x | + | 8 5 | x | × | 1 | + | 8 5 | x | x |
| = | 8 5 | + | 8 5 | x | + | 8 5 | x | + | 8 5 | x | x |
| = | 8 5 | + | 16 5 | x | + | 8 5 | x | x |
8 5 | + | 16 5 | x | + | 8 5 | x | x | = | 5 2 |
| x1= | - | 9 4 |
| x2= | 1 4 |