Question

a-9 a^2-3
2- ---- = ------
a+4 a +4 solve

Answer 1

common numerator on a right site:
[2(a+4) - (a-9)]/(a+4) = (a^2-3)/(a+4)
do you see that denominator is the same on both sides.. which is means that

Answer 2

numerators should be the same. so we can write that following:
2a+8-a+9=a^2-3
a^2-a-20=0
solve this quadratic equation for a

Answer 3

(x+4)(x-5)=0
x=-4 and x=5
the root a=-4 can not be the answer because you can delete by 0,
so there is only one answer:
x=5