please answer the questions about the following function

3. Answer the following about the function f(2) - 423 - 24 - 500. Justify all your answers. (a) Find all critical numbers of f(a) ( 2 pts) (b) Where is the function y = f(x) increasing? Justify your answer without graphing the function. ( 2 pts) (c) Where is the function y - f(r) concave down? Justify your answer without graphing the function. ( 2 pts) (d) Find the x-coordinate of the inflection point(s) of f(z) (1 pt)