| ( | 12000 | a | ) | ÷ | ( | 12000 | + | a | ) | = | 22239 50 |
| 方程两边同时乘以: | ( | 12000 | + | a | ) |
| ( | 12000 | a | ) | = | 22239 50 | ( | 12000 | + | a | ) |
| 12000 | a | = | 22239 50 | ( | 12000 | + | a | ) |
| 12000 | a | = | 22239 50 | × | 12000 | + | 22239 50 | a |
| 12000 | a | = | 5337360 | + | 22239 50 | a |
| 12000 | a | − | 22239 50 | a | = | 5337360 |
577761 50 | a | = | 5337360 |
| a | = | 5337360 | ÷ | 577761 50 |
| = | 5337360 | × | 50 577761 |
| = | 1779120 | × | 50 192587 |
| a | = | 88956000 192587 |
| a | = | 88956000 192587 |