| X | − | X | × | 3 50 | − | X | × | 1 20 | − | X | × | 3 20 | − | X | × | 3 20 | × | 1 4 | − | 40800 | = | 0 |
| 方程左边 = | X | − | X | × | 3 50 | − | X | × | 1 20 | − | X | × | 3 20 | − | X | × | 3 80 | − | 40800 |
| = | 281 400 | X | − | 40800 |
281 400 | X | − | 40800 | = | 0 |
281 400 | X | = | 0 | + | 40800 |
281 400 | X | = | 40800 |
| X | = | 40800 | ÷ | 281 400 |
| = | 40800 | × | 400 281 |
| X | = | 16320000 281 |
| X | = | 58078.291815 |