Problem 2. (5 points) We say that g(x) is a tight big-O bound for f(x) if f(x) = 0(g(x)) and for all h(x) such that f(x) = O(h(x)), g(x) = O(h(x)). Show that g(x) is a tight big-O bound for f(x) if and only if f(x) = 8(x)