| ( | 2 | − | x | ) | ( | 2 | − | x | ) | ( | 1 | − | x | ) | + | 2 | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) | + | ( | 2 | − | x | ) | = | 0 |
| 方程左边 = | 2 | ( | 2 | − | x | ) | ( | 1 | − | x | ) | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | + | 2 | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) | + | ( | 2 | − | x | ) |
| = | 2 | × | 2 | ( | 1 | − | x | ) | − | 2 | x | ( | 1 | − | x | ) | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | + | 2 | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) |
| = | 4 | ( | 1 | − | x | ) | − | 2 | x | ( | 1 | − | x | ) | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | + | 2 | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) | + | ( | 2 | − | x | ) |
| = | 4 | × | 1 | − | 4 | x | − | 2 | x | ( | 1 | − | x | ) | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | + | 2 | − | ( | 2 | − | x | ) |
| = | 4 | − | 4 | x | − | 2 | x | ( | 1 | − | x | ) | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | + | 2 | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) |
| = | 6 | − | 4 | x | − | 2 | x | ( | 1 | − | x | ) | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) | + | ( | 2 | − | x | ) |
| = | 6 | − | 4 | x | − | 2 | x | × | 1 | + | 2 | x | x | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) |
| = | 6 | − | 4 | x | − | 2 | x | + | 2 | x | x | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | − | ( | 2 | − | x | ) |
| = | 6 | − | 6 | x | + | 2 | x | x | − | x | ( | 2 | − | x | ) | ( | 1 | − | x | ) | − | ( | 2 | − | x | ) | + | ( | 1 | − | x | ) | + | ( | 2 | − | x | ) |
| = | 6 | − | 6 | x | + | 2 | x | x | − | x | × | 2 | ( | 1 | − | x | ) | + | x | x | ( | 1 | − | x | ) |
| = | 6 | − | 6 | x | + | 2 | x | x | − | x | × | 2 | × | 1 | + | x | × | 2 | x |
| = | 6 | − | 6 | x | + | 2 | x | x | − | x | × | 2 | + | x | × | 2 | x | + | x |
| = | 6 | − | 8 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | ( | 1 | − | x | ) |
| = | 6 | − | 8 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| = | 6 | − | 8 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| = | 4 | − | 7 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| = | 4 | − | 7 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| = | 5 | − | 8 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| = | 5 | − | 8 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| = | 7 | − | 9 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 |
| 7 | − | 9 | x | + | 2 | x | x | + | x | × | 2 | x | + | x | x | × | 1 | = | 0 |