Letter of the answer only

12) Which of the following would be the next step for calculating f' (1) for f (x) = 2x2 + 4? F(1) - lim (2x7 +4) -6 Step 1: X+1 x- 1 2(x + 2) (x - 1) A) ( - lim 2(x + 6)(x - 1) gr() - lim X+1 x-1 X+1 x- 1 B) () - lim 2(x + 1)(x-1) 2(x +6) DJ () - lim x+1 x- 1 r+1 x-1 13) Which of the following is the derivative of the function at a point in item number 12? A) 4 B) 6 C) 8 D) 10 14) Find all values of x (if any) where the tangent line to the graph of the function f(x) = x3- 12x +2 is horizontal ? A) - 2, 0, 2 BJ O C) 0, 2 DJ 2, - 2 15) The given limit represents the derivative of a function f at a number x. Which of the following is the f(q) and the x for lim (1+h)10 - 15 h+0 h A) f (x) = x10 ; x = -1 C) f (x) = 1 + h10 ; x = - 1 B) f (x) = (1 + h)10 ; x =-1 D) f (x) = x10; x = 1