| 3 | X | + | 7 | ( | X | − | 1 | ) | = | 3 | − | ( | X | − | 3 | ) | × | 1 2 |
| 方程左边 = | 3 | X | + | 7 | X | − | 7 | × | 1 |
| = | 3 | X | + | 7 | X | − | 7 |
| = | 10 | X | − | 7 |
| 10 | X | − | 7 | = | 3 | − | ( | X | − | 3 | ) | × | 1 2 |
| 方程右边 = | 3 | − | X | × | 1 2 | + | 3 | × | 1 2 |
| = | 3 | − | X | × | 1 2 | + | 3 2 |
| = | 9 2 | − | 1 2 | X |
| 10 | X | − | 7 | = | 9 2 | − | 1 2 | X |
| 10 | X | + | 1 2 | X | = | 9 2 | + | 7 |
21 2 | X | = | 9 2 | + | 7 |
21 2 | X | = | 23 2 |
| X | = | 23 2 | ÷ | 21 2 |
| = | 23 2 | × | 2 21 |
| = | 23 | × | 1 21 |
| X | = | 23 21 |
| X | = | 1.095238 |