Given the following functions:
f(x) = x^2 - 4, g(x) = √(x + 5), h(x) = 1/x
a) State the domain of g(x) in interval notation.
b) Find and simplify (h@g)(x).
c) State the domain of (h@g)(x) in interval notation.
d) Evaluate (h@g)(4).
e) Find and simplify (g@f)(x).