Answer:
x = -4
Explanation:
The axis of symmetry of a quadratic function must be equidistant from both branches of the parabola that the quadratic function describes. therefore, the axis of symmetry must be a vertical line that lies at exactly the middle point between the crossings of the parabola branches on the x axis.
These two crossings are the zeroes of the parabola (given as -12 and 4).
So we notice that the distance between these two points is 16 units: |12-(-4)| = 16. Therefore the axis of symmetry should be located at half distance from these two points, that is: at 8 units from each.
This makes the axis' position 8 units to the right of "-12", which gives x = -4.
Then the equation of the axis of symmetry for this quadratic function must be the vertical line defined by:
x = -4