Let $f(x)=\sqrt{4+x}$ and $g(x)=\sqrt{4-x}$.

Note: Each answer should be given in interval notation. Use inf for $\infty$ and -inf for $-\infty$.

(a) the domain of $f+g$ is

(b) the domain of $f-g$ is

(c) the domain of $fg$ is

(d) the domain of $f/g$ is