Formulae and Facts about Parabolas

1. Using y = ax² + bx + c
   • The y-intercept is (0, c)
2. Using y = a(x - h)² + k
   • The vertex is (h, k)
   • The y-intercept is (0, ah² + k)
3. Using y = ax(x - s) + t
   • The vertex is (s/2, t - as²/4)
   • The y-intercept is (0, t)