The domain of f is all reals.
The domain of g is all reals.
The domain of f/g, therefore is all reals EXCEPT where g(x) = 0, which is at x = 0.
Therefore, the domain of f/g is
x ≠ 0
or
x < 0 or x > 0 - with inequalities
or
(-∞, 0) ∪ (0, ∞) - interval notation