| x | ( | 1 10 | x | + | 1 | ) | ( | x | + | 1 | ) | + | 20 | = | 0 |
| 方程左边 = | x | × | 1 10 | x | ( | x | + | 1 | ) | + | x | × | 1 | ( | x | + | 1 | ) | + | 20 |
| = | x | × | 1 10 | x | x | + | x | × | 1 10 | x | × | 1 | + | x | × | 1 | ( | x | + | 1 | ) | + | 20 |
| = | x | × | 1 10 | x | x | + | x | × | 1 10 | x | + | x | × | 1 | ( | x | + | 1 | ) | + | 20 |
| = | x | × | 1 10 | x | x | + | x | × | 1 10 | x | + | x | × | 1 | x | + | x | × | 1 |
| = | x | × | 1 10 | x | x | + | x | × | 1 10 | x | + | x | × | 1 | x | + | x | × | 1 |
| x | × | 1 10 | x | x | + | x | × | 1 10 | x | + | x | × | 1 | x | + | 1 | x | = | 0 |