| X | + | 1 5 | X | + | 1 5 | ( | X | + | 1 5 | X | ) | + | 16200 | = | 270000 |
| 方程左边 = | 6 5 | X | + | 1 5 | ( | X | + | 1 5 | X | ) | + | 16200 |
6 5 | X | + | 1 5 | ( | X | + | 1 5 | X | ) | + | 16200 | = | 270000 |
| 方程左边 = | 6 5 | X | + | 1 5 | X | + | 1 5 | × | 1 5 | X | + | 16200 |
| = | 6 5 | X | + | 1 5 | X | + | 1 25 | X | + | 16200 |
| = | 36 25 | X | + | 16200 |
36 25 | X | + | 16200 | = | 270000 |
36 25 | X | = | 270000 | − | 16200 |
36 25 | X | = | 253800 |
| X | = | 253800 | ÷ | 36 25 |
| = | 253800 | × | 25 36 |
| = | 7050 | × | 25 |
| X | = | 176250 |