what are the correct answers? and why

6. Let f be a function defined on the [-5,5] with f(1) = 3. The graph of f', the derivative of f, consists of two semicircles and two line segments, as shown below. (2. 2) ( 5 , - 1 ) Graph of f* a. Find all values of x at which f has a relative maximum. Justify your answer. X = 2 Frel max x = /24 = 2 b. Find all values of x at which f has a point of inflection. Justify your answer. f info pt x = - 4 x 21 1 1- 1 c. Find all intervals on which the graph of f is concave up. Justify your answer. - 3 d. Find all intervals on which the graph of f has a positive slope. Justify your answer. (1 1 / 2 ) 1)