Answer:
x = -4
Explanation:
To determine the axis of symmetry, we need to find the vertex point.
Since the equation is already in vertex form, we can easily tell that the vertext point is (-4,-6)
We know the axis of symmetry is going to be vertical, and vertical lines are in the form of "x = ...".
Since we know x value of the vertex is -4, we know the line of symmetry will be x = -4