need help to solve please see attached

Flight of a Rocket The altitude (in feet) of a rocket t s into flight is given by s = f(t) = t3 + 45:2 + 560: + 6 (r 2 0). Find the point of inflection of the function f. ([35) =( 15 0) X What is the maximum velocity (in ft/s) attained by the rocket? :l/s