| x | x | = | 13 5 | ( | 1 | − | x | ) | ( | 4 | − | x | ) |
| 方程右边 = | 13 5 | × | 1 | ( | 4 | − | x | ) | − | 13 5 | x | ( | 4 | − | x | ) |
| = | 13 5 | ( | 4 | − | x | ) | − | 13 5 | x | ( | 4 | − | x | ) |
| = | 13 5 | × | 4 | − | 13 5 | x | − | 13 5 | x | ( | 4 | − | x | ) |
| = | 52 5 | − | 13 5 | x | − | 13 5 | x | ( | 4 | − | x | ) |
| = | 52 5 | − | 13 5 | x | − | 13 5 | x | × | 4 | + | 13 5 | x | x |
| = | 52 5 | − | 13 5 | x | − | 52 5 | x | + | 13 5 | x | x |
| = | 52 5 | − | 13 | x | + | 13 5 | x | x |
| x | x | = | 52 5 | − | 13 | x | + | 13 5 | x | x |