Considering the vertex of the graph, it is found that the quadratic function that is the best model for the data is given by:
[tex]y = -200(x - 4)^2 + 800[/tex]
The equation of a quadratic function, of vertex (h,k), is given by:
[tex]y = a(x - h)^2 + k[/tex]
In which a is the leading coefficient.
Researching the problem on the internet, it is found that the vertex is at point (4,800), hence h = 4 and k = 800.
[tex]y = a(x - 4)^2 + 800[/tex]
It has a value of y = 0 at x = 6, hence:
[tex]0 = a(6 - 4)^2 + 800[/tex]
[tex]a = -200[/tex]
Thus, the model is:
[tex]y = -200(x - 4)^2 + 800[/tex]
More can be learned about quadratic functions at https://brainly.com/question/24737967