Answer
The vertex is labeled with its coordinates, and the green line is the axis of symmetry.
Work Step by Step
$h(x)=-1/3*x^2$
$a=-1/3$, $b=0$, $c=-4$
The axis of symmetry is at $x=-b/2a$
$x=-b/2a$
$x=-0/2*-1/3$
$x=-0/-2/3$
$x=0$
The vertex is at $x=0$
$h(x)=-1/3*x^2$
$h(0)=-1/3*0^2$
$h(0)=-1/3*0$
$h(0)=0$
$(0, 0)$ is the vertex.