Let f (x) = x². Graph the functions f (x + 1), f (x - 1), f (x + 2), and f (x - 2). Make a guess about the relationship between the graph of a general function f (x) and the graph of f (g(x)), where g(x) = x + a for some constant a. Test your guess on the functions f (x) = x³ and f (x) = √x.