| 78 | ( | 1 | + | 1 10 | × | a% | ) | = | 26 | ( | 1 | + | a% | ) | + | 52 | ( | 1 | + | 5 | × | a% | ) |
| 方程左边 = | 78 | × | 1 | + | 78 | × | 1 10 | × | a% |
| = | 78 | + | 39 500 | a |
| 78 | + | 39 500 | a | = | 26 | ( | 1 | + | a% | ) | + | 52 | ( | 1 | + | 5 | × | a% | ) |
| 方程右边 = | 26 | × | 1 | + | 26 | × | a% | + | 52 | ( | 1 | + | 5 | × | a% | ) |
| = | 26 | + | 13 50 | a | + | 52 | ( | 1 | + | 5 | × | a% | ) |
| = | 26 | + | 13 50 | a | + | 52 | × | 1 | + | 52 | × | 5 | × | a% |
| = | 26 | + | 13 50 | a | + | 52 | + | 13 5 | a |
| = | 78 | + | 143 50 | a |
| 78 | + | 39 500 | a | = | 78 | + | 143 50 | a |
39 500 | a | − | 143 50 | a | = | 78 | − | 78 |
| - | 1391 500 | a | = | 78 | − | 78 |
| - | 1391 500 | a | = | 0 |
| - | 0 | = | 1391 500 | a |
1391 500 | a | = | - | 0 |
| a | = | - | 0 | ÷ | 1391 500 |
| = | - | 0 | × | 500 1391 |
| a | = | 0 |