| 30000 | ÷ | ( | a | + | 60 | ) | + | 10000 | ÷ | a | = | 150 |
| 方程两边同时乘以: | ( | a | + | 60 | ) |
| 30000 | + | 10000 | ÷ | a | × | ( | a | + | 60 | ) | = | 150 | ( | a | + | 60 | ) |
| 30000 | + | 10000 | ÷ | a | × | a | + | 10000 | ÷ | a | × | 60 | = | 150 | ( | a | + | 60 | ) |
| 30000 | + | 10000 | ÷ | a | × | a | + | 10000 | ÷ | a | × | 60 | = | 150 | a | + | 150 | × | 60 |
| 30000 | + | 10000 | ÷ | a | × | a | + | 600000 | ÷ | a | = | 150 | a | + | 9000 |
| 方程两边同时乘以: | a |
| 30000 | a | + | 10000 | ÷ | 1 | × | 1 | a | + | 600000 | = | 150 | a | a | + | 9000 | a |