The form of the quadratic function is
[tex]f(x)=ax^2+bx+c[/tex]a is the coefficient of x^2
If a > 0, then the function has a minimum vertex
If a < 0, then the function has a maximum vertex
In the given function
[tex]f(x)=-x^2+8x-20[/tex]The value of a = -1
Since -1 < 0, then
The given function has a maximum vertex
The function has a maximum value
The graph of the function
Its vertex point is a maximum point (4, -4)
Its maximum value is -4
