| ( | 18000 | + | 9000 | − | 1000 | x | ) | ÷ | ( | 1000 | x | ) | = | 30 100 |
| 方程两边同时乘以: | ( | 1000 | x | ) |
| ( | 18000 | + | 9000 | − | 1000 | x | ) | = | 30 100 | ( | 1000 | x | ) |
| 18000 | + | 9000 | − | 1000 | x | = | 30 100 | ( | 1000 | x | ) |
| 18000 | + | 9000 | − | 1000 | x | = | 30 100 | × | 1000 | x |
| 18000 | + | 9000 | − | 1000 | x | = | 300 | x |
| 27000 | − | 1000 | x | = | 300 | x |
| - | 1000 | x | − | 300 | x | = | - | 27000 |
| - | 1300 | x | = | - | 27000 |
| 27000 | = | 1300 | x |
| 1300 | x | = | 27000 |
| x | = | 27000 | ÷ | 1300 |
| = | 27000 | × | 1 1300 |
| = | 270 | × | 1 13 |
| x | = | 270 13 |
| x | = | 20.769231 |