Answer:
x = -6
Explanation:
The axis of symmetry represents the x - value of a parabola. The axis of symmetry is known as the "peak" of the parabola. The "peak" as in the point in the parabola where you see the direction start to go downwards/upwards again. When using the point of the "peak", your axis of symmetry would only be the x - value.
For example:
The "peak" point is (-6, 6). Your x - coordinate is -6 and your y - coordinate is 6. Since the axis of symmetry only focuses on the x - value, then your axis of symmetry would be x = -6