The equation for the axis of symmetry is x = 4
What is axis of symmetry of a parabola
The axis of symmetry of a parabola is a vertical line that passes through the vertex of the parabola, dividing it into two symmetrical halves.
The is the x coordinate of a vertical parabola.
Investigating the graph, the vertical line of symmetry is located at x = 4. This is the axis of symmetry