Complete the square to write f(x) = x2 + 6x + 14 in vertex form. a. f(x) = (x + 3)2 + 5 b. f(x) = (x - 3)2 + 14 C. f(x) = (x + 3)2 + 23 d. f(x) = (x + 6)2 + 14