Question 174318
Your function is a second degree polynomial in {{{v}}}, meaning that the graph of the function will be a parabola.  Since the lead coefficient is less than zero, you have a parabola that is concave down and you know for sure that the vertex of the parabola is a maximum point.


For any parabola expressed in the form {{{f(x)=ax^2+bx+c}}}, the vertex is located at the point ({{{-b/2a)}}},{{{f(-b/2a)}}}).


All you need to do is calculate {{{v[mfe]=-b/2a=-2.768/(2*(-0.0235))}}} to determine the velocity that gives the maximum fuel efficiency and then evaluate the function for {{{f(v[mfe])}}} to determine the fuel efficiency at that velocity.