a^2-9/a^2+6a+9/a-3/a^2+3a-a-a^2/a^2-1怎么化简
问题描述：
a^2-9/a^2+6a+9/a-3/a^2+3a-a-a^2/a^2-1怎么化简
答
原式=[(a+3)(a-3)/(a+3)²]*[a(a+3)/(a-3)]+a(a-1)/(a+1)(a-1)
=a+a/(a+1)
=(a²+2a)/(a+1)