| - | ( | 1 | − | x | ) | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) | + | 4 | ( | 1 | − | x | ) | = | 0 |
| 方程左边 = | - | 1 | ( | 2 | − | x | ) | ( | 3 | + | x | ) | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) | + | 4 | ( | 1 | − | x | ) |
| = | - | 1 | × | 2 | ( | 3 | + | x | ) | + | 1 | x | ( | 3 | + | x | ) | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) | + | 4 |
| = | - | 2 | ( | 3 | + | x | ) | + | 1 | x | ( | 3 | + | x | ) | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) | + | 4 | ( | 1 | − | x | ) |
| = | - | 2 | × | 3 | − | 2 | x | + | 1 | x | ( | 3 | + | x | ) | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) |
| = | - | 6 | − | 2 | x | + | 1 | x | ( | 3 | + | x | ) | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) | + | 4 |
| = | - | 6 | − | 2 | x | + | 1 | x | × | 3 | + | 1 | x | x | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) |
| = | - | 6 | − | 2 | x | + | 3 | x | + | 1 | x | x | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 |
| = | - | 6 | + | 1 | x | + | 1 | x | x | + | x | ( | 2 | − | x | ) | ( | 3 | + | x | ) | − | 4 | ( | 3 | + | x | ) | + | 4 |
| = | - | 6 | + | 1 | x | + | 1 | x | x | + | x | × | 2 | ( | 3 | + | x | ) | − | x | x | ( | 3 | + | x | ) |
| = | - | 6 | + | 1 | x | + | 1 | x | x | + | x | × | 2 | × | 3 | + | x | × | 2 | x |
| = | - | 6 | + | 1 | x | + | 1 | x | x | + | x | × | 6 | + | x | × | 2 | x | − | x |
| = | - | 6 | + | 7 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | ( | 3 | + | x | ) |
| = | - | 6 | + | 7 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| = | - | 6 | + | 7 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| = | - | 6 | + | 7 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| = | - | 18 | + | 3 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| = | - | 18 | + | 3 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| = | - | 18 | + | 3 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| = | - | 14 | − | 1 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 |
| - | 14 | − | 1 | x | + | 1 | x | x | + | x | × | 2 | x | − | x | x | × | 3 | = | 0 |