| 1+a | 1−2a | a(1−a) | |||
− | − | ||||
| a−3 | 3+a | 9−a2 |
| 1+a | 1−2a | a(1−a) | |||
− | − | = | |||
| a−3 | 3+a | 9−a2 |
| 1+a | 1−2a(3−a) | a(1−a) | ||||
= | − | − | = | |||
| a−3 | (3+a)(3−a) | (3−a)(3+a) |
| 1+a | 1−2a(3−a)−a(1−a) | |||
= −1( | ) − | = | ||
| 3−a | (3−a)(3+a) |
| (1+a)(3+a) | 1−2a(3−a)−a(1−a) | |||
= −1( | ) − | = | ||
| (3−a)(3+a) | (3−a)(3+a) |
| (1+a)(3+a)−[1−2a(3−a)−a(1−a)] | ||
= −1 | = | |
| (3−a)(3+a) |
