| ( | x | − | 61 | ) | ( | x | − | 25 | ) | − | 38 | × | 38 | = | 0 |
| 方程左边 = | ( | x | − | 61 | ) | ( | x | − | 25 | ) | − | 1444 |
| ( | x | − | 61 | ) | ( | x | − | 25 | ) | − | 1444 | = | 0 |
| 方程左边 = | x | ( | x | − | 25 | ) | − | 61 | ( | x | − | 25 | ) | − | 1444 |
| = | x | x | − | x | × | 25 | − | 61 | ( | x | − | 25 | ) | − | 1444 |
| = | x | x | − | 25 | x | − | 61 | x | + | 61 | × | 25 | − | 1444 |
| = | x | x | − | 25 | x | − | 61 | x | + | 1525 | − | 1444 |
| = | x | x | − | 86 | x | + | 81 |
| x | x | − | 86 | x | + | 81 | = | 0 |