13. Which graph represents the function f(x) = -1 C. 0 2 4 - 4 b. d. 2 4 2 2 14. Find f "(x) if f(x) = x2+ 2 a. 2+- c. 2+ 3 2x x b. 2+ - 3 2NX d. 2- 15. If f(x) = ax + , where a and b are constants, find f "(x). a. at b C. b. a+ 2b d. 2b 3