| X | + | 1 5 | X | + | 1 5 | ( | X | + | 1 5 | X | ) | + | 2700 | = | 45000 |
| 方程左边 = | 6 5 | X | + | 1 5 | ( | X | + | 1 5 | X | ) | + | 2700 |
6 5 | X | + | 1 5 | ( | X | + | 1 5 | X | ) | + | 2700 | = | 45000 |
| 方程左边 = | 6 5 | X | + | 1 5 | X | + | 1 5 | × | 1 5 | X | + | 2700 |
| = | 6 5 | X | + | 1 5 | X | + | 1 25 | X | + | 2700 |
| = | 36 25 | X | + | 2700 |
36 25 | X | + | 2700 | = | 45000 |
36 25 | X | = | 45000 | − | 2700 |
36 25 | X | = | 42300 |
| X | = | 42300 | ÷ | 36 25 |
| = | 42300 | × | 25 36 |
| = | 1175 | × | 25 |
| X | = | 29375 |