Question

A parabola has x-intercepts x= 3 and x= -9. How do you determine the equation of the axis of symmetry for the parabola?

Answer 1

x = - 3

Explanation:

Call x the x-coordinate of the parabola axis of symmetry:
Call x1 = 3 and x2 = -9, the two x-intercepts.
The coordinate of the of the parabola 's axis of symmetry is:
`x = (x1 + x2)/2 = (3 - 9)/2 = - 3`