| 75 | = | ( | X | + | 40 | + | 9 | + | 7 | ) | + | 9 2 | ( | X | + | 40 | + | 9 | + | 7 | ) |
| 方程右边 = | X | + | 40 | + | 9 | + | 7 | + | 9 2 | ( | X | + | 40 | + | 9 | + | 7 | ) |
| = | X | + | 56 | + | 9 2 | ( | X | + | 40 | + | 9 | + | 7 | ) |
| = | X | + | 56 | + | 9 2 | X | + | 9 2 | × | 40 | + | 9 2 | × | 9 | + | 9 2 | × | 7 |
| = | X | + | 56 | + | 9 2 | X | + | 180 | + | 81 2 | + | 63 2 |
| = | 11 2 | X | + | 308 |
| 75 | = | 11 2 | X | + | 308 |
| - | 11 2 | X | = | 308 | − | 75 |
| - | 11 2 | X | = | 233 |
| - | 233 | = | 11 2 | X |
11 2 | X | = | - | 233 |
| X | = | - | 233 | ÷ | 11 2 |
| = | - | 233 | × | 2 11 |
| X | = | - | 466 11 |
| X | = | - 42.363636 |