2 5 | ( | 1 | + | x | ) | ( | 1 | + | x | ) | = | 56 |
| 方程左边 = | 2 5 | × | 1 | ( | 1 | + | x | ) | + | 2 5 | x | ( | 1 | + | x | ) |
| = | 2 5 | ( | 1 | + | x | ) | + | 2 5 | x | ( | 1 | + | x | ) |
| = | 2 5 | × | 1 | + | 2 5 | x | + | 2 5 | x | ( | 1 | + | x | ) |
| = | 2 5 | + | 2 5 | x | + | 2 5 | x | ( | 1 | + | x | ) |
| = | 2 5 | + | 2 5 | x | + | 2 5 | x | × | 1 | + | 2 5 | x | x |
| = | 2 5 | + | 2 5 | x | + | 2 5 | x | + | 2 5 | x | x |
| = | 2 5 | + | 4 5 | x | + | 2 5 | x | x |
2 5 | + | 4 5 | x | + | 2 5 | x | x | = | 56 |