What is the equation of the axis of symmetry of a parabola if its x-intercepts are -3 and 7?

This is a parabola, meaning the equation is a quadratic, so it has 2 roots or x-intercepts, keeping in mind that vertex will lie half-way between those intercepts.

so what's the x-value halfway between -3 and 7?  yeap, you guessed it, 2.

so the axis of symmetry for this vertical parabola will be at x = 2.

Agc and bgd are vertical angles