| ( | 50 | − | 2 | x | ) | ( | 38 | − | 2 | x | ) | × | 1260 | = | 0 |
| 方程左边 = | 50 | ( | 38 | − | 2 | x | ) | × | 1260 | − | 2 | x | ( | 38 | − | 2 | x | ) | × | 1260 |
| = | 63000 | ( | 38 | − | 2 | x | ) | − | 2520 | x | ( | 38 | − | 2 | x | ) |
| = | 63000 | × | 38 | − | 63000 | × | 2 | x | − | 2520 | x | ( | 38 | − | 2 | x | ) |
| = | 2394000 | − | 126000 | x | − | 2520 | x | ( | 38 | − | 2 | x | ) |
| = | 2394000 | − | 126000 | x | − | 2520 | x | × | 38 | + | 2520 | x | × | 2 | x |
| = | 2394000 | − | 126000 | x | − | 95760 | x | + | 5040 | x | x |
| = | 2394000 | − | 221760 | x | + | 5040 | x | x |
| 2394000 | − | 221760 | x | + | 5040 | x | x | = | 0 |