There MIGHT (probably) be an easier way, but here is ONE way:
(x+(-3-sqrt5))(x+(-3+sqrt5)) is given in the question for the roots
if you multiply these two term out you will get
x^2-6x+4 now multiply by -2
-2x^2 +12x-8 =0 (a parabola)
to find vertex take derivative and set equal to zero
-4x+12 = 0 x = 3 substitue this into the equation
to get y=10 for the vertex 3,10