通分：（a-1）/（a²+2a+1）,6/（a²-1）
问题描述：
通分：（a-1）/（a²+2a+1）,6/（a²-1）
答
a²+2a+1=(a+1)²
a²-1=(a+1)(a-1)
∴它们的最简公分母是(a+1)²(a-1)
（a-1）/（a²+2a+1）=(a-1)/(a+1)²=(a-1)²/(a+1)²(a-1)
6/（a²-1）=6/(a+1)(a-1)=6(a+1)/(a+1)²(a-1)
答
（a-1）/（a²+2a+1）
=（a-1）/（a+1）²
=（a-1）²/（a-1）（a+1）²
6/（a²-1）
=6/（a-1）（a+1）
=6（a-1）/（a-1）（a+1）²
答
a²+2a+1=(a+1)²
a²-1=(a+1)(a-1)
最简公分母是(a+1)²(a-1)
所以
（a-1）/（a²+2a+1）=(a-1)²/(a+1)²(a-1)
6/（a²-1）=6(a+1)/(a+1)²(a-1)