| ( | 50 | ( | 1 | − | 2 5 | × | a% | ) | − | 27 | ) | ( | 12000 | ( | 1 | + | a% | ) | ) | = | 252000 |
| 方程左边 = | 50 | ( | 1 | − | 2 5 | × | a% | ) | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 50 | × | 1 | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 50 | × | 2 5 | × | a% | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 50 | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 1 5 | a | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 50 | × | 12000 | ( | 1 | + | a% | ) | − | 1 5 | a | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | ( | 1 | + | a% | ) | − | 1 5 | a | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | × | 1 | + | 600000 | × | a% | − | 1 5 | a | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 6000 | a | − | 1 5 | a | ( | 12000 | ( | 1 | + | a% | ) | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 6000 | a | − | 1 5 | a | × | 12000 | ( | 1 | + | a% | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 6000 | a | − | 2400 | a | ( | 1 | + | a% | ) | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 6000 | a | − | 2400 | a | × | 1 | − | 2400 | a | × | a% | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 6000 | a | − | 2400 | a | − | 24 | a | a | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 3600 | a | − | 24 | a | a | − | 27 | ( | 12000 | ( | 1 | + | a% | ) | ) |
| = | 600000 | + | 3600 | a | − | 24 | a | a | − | 27 | × | 12000 | ( | 1 | + | a% | ) |
| = | 600000 | + | 3600 | a | − | 24 | a | a | − | 324000 | ( | 1 | + | a% | ) |
| = | 600000 | + | 3600 | a | − | 24 | a | a | − | 324000 | × | 1 | − | 324000 | × | a% |
| = | 600000 | + | 3600 | a | − | 24 | a | a | − | 324000 | − | 3240 | a |
| = | 276000 | + | 360 | a | − | 24 | a | a |
| 276000 | + | 360 | a | − | 24 | a | a | = | 252000 |