| 1 | + | ( | 3 100 | + | x | ) | ( | 47 20 | + | 10 | x | ) | = | 0 |
| 方程左边 = | 1 | + | 3 100 | ( | 47 20 | + | 10 | x | ) | + | x | ( | 47 20 | + | 10 | x | ) |
| = | 1 | + | 3 100 | × | 47 20 | + | 3 100 | × | 10 | x | + | x | ( | 47 20 | + | 10 | x | ) |
| = | 1 | + | 141 2000 | + | 3 10 | x | + | x | ( | 47 20 | + | 10 | x | ) |
| = | 2141 2000 | + | 3 10 | x | + | x | ( | 47 20 | + | 10 | x | ) |
| = | 2141 2000 | + | 3 10 | x | + | x | × | 47 20 | + | x | × | 10 | x |
| = | 2141 2000 | + | 53 20 | x | + | x | × | 10 | x |
2141 2000 | + | 53 20 | x | + | x | × | 10 | x | = | 0 |