Question 440163
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Hi
The number of fruit flies F(x) in a farming area depends on the spring rainfall x: 
 f(x) = -x^2+15x  |graphically a parabola opening downward a< 0
Using the vertex form of a parabola, {{{y=a(x-h)^2 +k}}} where(h,k) is the vertex
 f(x) = -(x -7.5)^2 + 56.25     | completing the square to find the vertex
 Vertex is Pt(7.5, 56.25)
     7.5" rainfall produces the maximum number of fruit flies