| - | 7 10 | × | 3 10 | = | ( | 832 25 | − | x | ) | ( | 684 25 | − | x | ) |
| 方程左边 = | - | 21 100 |
| - | 21 100 | = | ( | 832 25 | − | x | ) | ( | 684 25 | − | x | ) |
| 方程右边 = | 832 25 | ( | 684 25 | − | x | ) | − | x | ( | 684 25 | − | x | ) |
| = | 832 25 | × | 684 25 | − | 832 25 | x | − | x | ( | 684 25 | − | x | ) |
| = | 569088 625 | − | 832 25 | x | − | x | ( | 684 25 | − | x | ) |
| = | 569088 625 | − | 832 25 | x | − | x | × | 684 25 | + | x | x |
| = | 569088 625 | − | 1516 25 | x | + | x | x |
| - | 21 100 | = | 569088 625 | − | 1516 25 | x | + | x | x |