Question 1100535
Vertex is minus the -3 and plus the 6 or (3, 6)
axis of symmetry is around x=3
{{{graph(300,300,-10,10,-10,10,(-1/2)(x+3)^2+6,(-1/2)x^2-3x-4.5+6)}}}
check by (-1/2)(x^2+6x+9)+6
This is (-1/2)x^2-3x-4.5+6
or -(1/2)x^2-3x+1.5
vertex x-value and axis of symmetry is at -b/2a=3/-1=-3