| 20 | + | 2000 | ÷ | x | − | 90 | x | − | 8000 | ÷ | ( | ( | x | − | 1 | ) | x | ) | = | 0 |
| 方程两边同时乘以: | x |
| 20 | x | + | 2000 | − | 90 | x | x | − | 8000 | ÷ | ( | ( | x | − | 1 | ) | × | 1 | ) | × | 1 | = | 0 |
| 方程两边同时乘以: | ( | ( | x | − | 1 | ) | × | 1 | ) |
| 20 | x | ( | ( | x | − | 1 | ) | × | 1 | ) | + | 2000 | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 8000 | × | 1 | = | 0 |
| 20 | x | ( | x | − | 1 | ) | × | 1 | + | 2000 | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 8000 | × | 1 | = | 0 |
| 20 | x | ( | x | − | 1 | ) | + | 2000 | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 8000 | = | 0 |
| 20 | x | x | − | 20 | x | × | 1 | + | 2000 | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | = | 0 |
| 20 | x | x | − | 20 | x | + | 2000 | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 8000 | = | 0 |
| 20 | x | x | − | 20 | x | + | 2000 | ( | x | − | 1 | ) | × | 1 | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | = | 0 |
| 20 | x | x | − | 20 | x | + | 2000 | ( | x | − | 1 | ) | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | − | 8000 | = | 0 |
| 20 | x | x | − | 20 | x | + | 2000 | x | − | 2000 | × | 1 | − | 90 | x | x | = | 0 |
| 20 | x | x | − | 20 | x | + | 2000 | x | − | 2000 | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | = | 0 |
| 20 | x | x | + | 1980 | x | − | 10000 | − | 90 | x | x | ( | ( | x | − | 1 | ) | × | 1 | ) | = | 0 |
| 20 | x | x | + | 1980 | x | − | 10000 | − | 90 | x | x | ( | x | − | 1 | ) | × | 1 | = | 0 |
| 20 | x | x | + | 1980 | x | − | 10000 | − | 90 | x | x | ( | x | − | 1 | ) | = | 0 |
| 20 | x | x | + | 1980 | x | − | 10000 | − | 90 | x | x | x | + | 90 | x | = | 0 |
| 20 | x | x | + | 1980 | x | − | 10000 | − | 90 | x | x | x | + | 90 | x | = | 0 |