Answer:
x = -2
Explanation:
a parabola is symmetric (has a mirror image)
a parabola has ONE vertex (a highest or lowest point).
thus a line that goes through the vertex is it's axis of symmetry.
x = 5 , x=99, x=102 are vertical lines that intersect the x axis no matter what the y value is....
your axis of symmetry is a line that looks like X= SOMETHING
the "something" is the X value of the vertex, which is (-2,3)
this the equation x = -2 is the answer ... see the image