Answer:
x = -7 or y = 1
Explanation:
Since we are not given the actual formula for the parabola, we do not know in which direction the parabola is facing. The axis of symmetry is the value of the line that splits the parabola perfectly down the middle, to calculate this we need to know in which direction the parabola is facing. Since we do not have this information and only have the maximum vertex we can provide the two possible values for the Axis of Symmetry, which would be the following...
x = -7 or y = 1