Answer:
(a+2)/(a-1)
Step-by-step explanation:
[(a^2+5a+6)/(a^2-1)]/[(a^2-9)(a^2-2a-3)]
[(a^2+5a+6)/(a^2-1)]*[(a^2-2a-3)(a^2-9)]
[(a^2+3a+2a+6)/(a-1)(a+1)]*[(a^2-3a+a-3)/(a-3)(a+3)]
[a(a+3)+2(a+3)/(a-1)(a+1)]*[(a(a-3)+1(a-3)/(a-3)(a+3)]
[(a+2)(a+3)/(a-1)(a+1)]*[(a+1)(a-3)/(a-3)(a+3)]
=(a+2)/(a-1)
