| X | − | 1 | ÷ | 4 | × | X | − | ( | 2 | ÷ | 5 | × | X | − | 7 | ) | = | 35 |
| 方程左边 = | X | − | 1 4 | X | − | ( | 2 | ÷ | 5 | × | X | − | 7 | ) |
| = | 3 4 | X | − | ( | 2 | ÷ | 5 | × | X | − | 7 | ) |
3 4 | X | − | ( | 2 | ÷ | 5 | × | X | − | 7 | ) | = | 35 |
| 方程左边 = | 3 4 | X | − | 2 | ÷ | 5 | × | X | + | 7 |
| = | 3 4 | X | − | 2 5 | X | + | 7 |
| = | 7 20 | X | + | 7 |
7 20 | X | + | 7 | = | 35 |
7 20 | X | = | 35 | − | 7 |
7 20 | X | = | 28 |
| X | = | 28 | ÷ | 7 20 |
| = | 28 | × | 20 7 |
| = | 4 | × | 20 |
| X | = | 80 |