a^2-4/3a+24÷a^3-4a/a^2+7a-8+1/3a
=(a+2)(a-2)/[3(a+8)]*(a+8)(a-1)/[a(a+2)(a-2)]+1/3a
=(a-1)/3a+1/3a
=(a-1+1)/3a
=a/3a
=1/3