Your f(x)=sqrt[x+8]/(x+4)(x-6) is MUCH clearer, but not 100% clear. I will assume that your denominator here is the product of (x+4) and (x-6):
√x+8)
f(x) = ------------------
(x+4)(x-6)
We cannot divide by zero. Thus, x cannot be -4 and cannot be 6.
Thus, the domain is:
(-infinity, -4) or (-4, 6) or (6, infinity).