Question

look at this graph:
graph with vertex at (0,0) opening downward
what is the equation of the axis of symmetry?

Explanation:

Step1: Identify parabola's vertex

The vertex is at $(0,0)$.

Step2: Find axis of symmetry

For a parabola, axis of symmetry is vertical line through vertex: $x = 0$.

Answer:

$x = 0$