Find the number of injections f from S = {1, 2, 3, 4, 5} to T = {a, b, c, d, e, f, g}, such that f(1)a and f(2) b. Important All of your solutions must be clearly justified with explanations and you must write each of your final answer in two ways. As a formula involving only products, sums, differences, or powers. As one final concrete number (where you might need to make use of a calculator)