Consider f(y) = - 13y- 4+4y Determine the intervals on which f is concave down. Of is concave down on: Of is concave down nowhere. Determine the intervals on which f is concave up. Of is concave up on: Of is concave up nowhere. Determine the value and location of any inflection point of f. Enter the solution in (y, f(y)) form. If multiple solutions exist, use a comma-separated list to enter the solutions. Of has an inflection point at: Of has no inflection point.