Question

Excluded value of a+2/a²-9

Answer 1

ac{a^{3}-9a^{2}+2}{a^{2}}

Answer 2

I will assume you meant
(a+2)/(a²-9)
= (a+2)/((a+2)(a-2))
= 1/(a-2) , a ≠ 2

some authors would have the exclusion as x ≠ ± 2
I have used the implicit format.

my final result would be
(a+2)/(a²-9) = 1/(a-2) , x ≠ 2

I left out the +2, since x = 2 would not work in the original, nor the final, so we don't really have to say anything about it, it would be implied.
Check with your instructor, your textbook, or your notes to see
which version is required for your course.

Answer 3

(a+2)/(a^2 - 9) = (a+2)/((a+3)(a-3))
defined everywhere except a = ±3