x | − | x | x | = | 9 | x | x | ( | 1 | − | x | ) | ( | 1 | − | x | ) |
方程右边 = | 9 | x | x | × | 1 | ( | 1 | − | x | ) | − | 9 | x | x | x | ( | 1 | − | x | ) |
= | 9 | x | x | ( | 1 | − | x | ) | − | 9 | x | x | x | ( | 1 | − | x | ) |
= | 9 | x | x | × | 1 | − | 9 | x | x | x | − | 9 | x | x | x |
= | 9 | x | x | − | 9 | x | x | x | − | 9 | x | x | x | ( | 1 | − | x | ) |
= | 9 | x | x | − | 9 | x | x | x | − | 9 | x | x | x | × | 1 |
= | 9 | x | x | − | 9 | x | x | x | − | 9 | x | x | x | + | 9 |
x | − | x | x | = | 9 | x | x | − | 9 | x | x | x | − | 9 | x | x | x | + | 9 |
x2=1 |