Find f+g, fg, fg, and f/g and their domains. f(x) = 3x, g(x) = x - 4 Find (f + g)(x). Find the domain of (f+ g)(x). (Enter your answer using interval notation.) Find (f-g)(x). Find the domain of (f-g)(x). (Enter your answer using interval notation.) Find (fg)(x). Find the domain of (fg)(x). (Enter your answer using interval notation.) Find (4)(x). Find the domain of (4)(x). (Enter your answer using interval notation.)