| X | − | 1 5 | X | − | 1 20 | X | − | 3 | = | 693 50 | + | 1 5 | × | 693 50 |
| 方程左边 = | 3 4 | X | − | 3 |
3 4 | X | − | 3 | = | 693 50 | + | 1 5 | × | 693 50 |
| 方程右边 = | 693 50 | + | 693 250 |
| = | 2079 125 |
3 4 | X | − | 3 | = | 2079 125 |
3 4 | X | = | 2079 125 | + | 3 |
3 4 | X | = | 2454 125 |
| X | = | 2454 125 | ÷ | 3 4 |
| = | 2454 125 | × | 4 3 |
| = | 818 125 | × | 4 |
| X | = | 3272 125 |
| X | = | 26.176 |