| ( | ( | 10 | − | x | ) | × | 10 | + | x | ) | ( | 10 | x | + | 10 | − | x | ) | = | 0 |
| 方程左边 = | ( | 10 | − | x | ) | × | 10 | ( | 10 | x | + | 10 | − | x | ) | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 10 | × | 10 | ( | 10 | x | + | 10 | − | x | ) | − | x | × | 10 | ( | 10 | x | + | 10 | − | x | ) | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 100 | ( | 10 | x | + | 10 | − | x | ) | − | x | × | 10 | ( | 10 | x | + | 10 | − | x | ) | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 100 | × | 10 | x | + | 100 | × | 10 | − | 100 | x | − | x | × | 10 | ( | 10 | x | + | 10 | − | x | ) | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 1000 | x | + | 1000 | − | 100 | x | − | x | × | 10 | ( | 10 | x | + | 10 | − | x | ) | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 900 | x | + | 1000 | − | x | × | 10 | ( | 10 | x | + | 10 | − | x | ) | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 900 | x | + | 1000 | − | x | × | 10 | × | 10 | x | − | x | × | 10 | × | 10 | + | x | × | 10 |
| = | 900 | x | + | 1000 | − | x | × | 100 | x | − | x | × | 100 | + | x | × | 10 | x | + | x |
| = | 800 | x | + | 1000 | − | x | × | 100 | x | + | x | × | 10 | x | + | x | ( | 10 | x | + | 10 | − | x | ) |
| = | 800 | x | + | 1000 | − | x | × | 100 | x | + | x | × | 10 | x | + | x | × | 10 | x |
| = | 810 | x | + | 1000 | − | x | × | 100 | x | + | x | × | 10 | x | + | x | × | 10 | x |
| 810 | x | + | 1000 | − | x | × | 100 | x | + | x | × | 10 | x | + | x | × | 10 | x | = | 0 |
| x1= | - | 10 9 |
| x2= | 100 9 |