A quadratic of the form $-2x^2 + bx + c$ has roots of $x = 3 + \sqrt{5}$ and $x = 3 - \sqrt{5}.$ The graph of $y = -2x^2 + bx + c$ is a parabola. Find the vertex of this parabola.
( x -3 + sqrt5)(x-3-sqrt5) is the eqution given the roots supplied
Multiply all of this out to get
x^2-6x+4 now multiply by -2 to get the same form as the question
-2x^2+12x-8
this is a dome shaped parabola max value will be at x = -b/2a = -12/-4 = 3
plug this into the equation to find y -2(3^2)+12(3) - 8 = y = 10
Vertex = (3,10)