1/a^2-2a+1,1/a^2-1,1/a^2+2a+1通分

问题描述:

1/a^2-2a+1,1/a^2-1,1/a^2+2a+1通分

(a+1)^2/(a+1)^2(a-1)^2,(a+1)(a-1)/(a+1)^2(a-1)^2,(a-1)^2/(a+1)^2(a-1)^2它们的公分母是什么?(a+1)^2(a-1)^2