<PRE><B>Question 42021</B>
This is a parabola that opens downward, and the vertex (maximum point) will be at {{{x=(-b)/(2a)}}}.  In this case, vertex is at {{{x= (-6)/(-2)=3}}}.


If x = 3, then y = -3^2 + 6*3= -9 + 18 = 9.  


Maximum value is 9.  Check it out with the graph:


{{{graph(300,300, -6,10, -4, 12, -x^2+6x)}}}


R^2 at SCC</PRE>