| x | ( | 1 5 | x | + | 1 | ) | ( | 1 10 | x | + | 1 | ) | = | 30 |
| 方程左边 = | x | × | 1 5 | x | ( | 1 10 | x | + | 1 | ) | + | x | × | 1 | ( | 1 10 | x | + | 1 | ) |
| = | x | × | 1 5 | x | × | 1 10 | x | + | x | × | 1 5 | x | × | 1 | + | x | × | 1 | ( | 1 10 | x | + | 1 | ) |
| = | x | × | 1 50 | x | x | + | x | × | 1 5 | x | + | x | × | 1 | ( | 1 10 | x | + | 1 | ) |
| = | x | × | 1 50 | x | x | + | x | × | 1 5 | x | + | x | × | 1 | × | 1 10 | x | + | x |
| = | x | × | 1 50 | x | x | + | x | × | 1 5 | x | + | x | × | 1 10 | x | + | x | × | 1 |
| x | × | 1 50 | x | x | + | x | × | 1 5 | x | + | x | × | 1 10 | x | + | 1 | x | = | 30 |