What is the concave upward? I have used the answers [-27, infinity), (-infinity, 0) and (0, infinity), (-infinity, 0) U (0, infinity), and DNE but they were all wrong

Find the point of inflection of the graph of the function. (If an answer does not exist, enter DNE.) f(x) = XVx+ 27 ( x, y ) = DNE Determine the open intervals on which the graph of the function is concave upward or concave downward. (Ent concave upward concave downward DNE