| ( | 100 | − | x | ) | ( | 98 | − | x | ) | − | 99 | × | 99 | = | 0 |
| 方程左边 = | ( | 100 | − | x | ) | ( | 98 | − | x | ) | − | 9801 |
| ( | 100 | − | x | ) | ( | 98 | − | x | ) | − | 9801 | = | 0 |
| 方程左边 = | 100 | ( | 98 | − | x | ) | − | x | ( | 98 | − | x | ) | − | 9801 |
| = | 100 | × | 98 | − | 100 | x | − | x | ( | 98 | − | x | ) | − | 9801 |
| = | 9800 | − | 100 | x | − | x | ( | 98 | − | x | ) | − | 9801 |
| = | - | 1 | − | 100 | x | − | x | ( | 98 | − | x | ) |
| = | - | 1 | − | 100 | x | − | x | × | 98 | + | x | x |
| = | - | 1 | − | 198 | x | + | x | x |
| - | 1 | − | 198 | x | + | x | x | = | 0 |