Final answer:
The domain of the function f(x) = square root of (x - 4) is x is greater than or equal to 4.
Step-by-step explanation:
The function f(x) = square root of (x - 4) has a restriction on its domain. Since we are taking the square root of (x - 4), the expression inside the square root must be non-negative. In other words, x - 4 must be greater than or equal to 0. Solving for x, we get x is greater than or equal to 4.