Question

look at this graph:
what is the equation of the axis of symmetry?

Explanation:

Step1: Identify parabola vertex

The vertex of the parabola is at $(0, -9)$, which lies on the axis of symmetry.

Step2: Determine symmetry line

For a vertical parabola, the axis of symmetry is a vertical line passing through the vertex, with equation $x = h$ where $h$ is the x-coordinate of the vertex.
<Expression>
$x = 0$
</Expression>

Answer:

$x=0$