If using the method of completing the square to solve the quadratic equation x² - 16x - 38 = 0, which number would have to be added to "complete the square"?

Someone answer this asap for the function f(x) and g(x) are both quadratic functions. f(x) = x² + 2x + 5 g(x) = x² + 2x - 1 which statement best describes the graph of g(x) compared to the graph of f(x)? a. the graph of g(x) is the graph of f(x) shifted down 1 units. b. the graph of g(x) is the graph of f(x) shifted down 6 units. c. the graph of g(x) is the graph of f(x) shifted to the right 1 unit. d. the graph of g(x) is the graph of f(x) shifted tothe right 6 units.