def parabola_vertex(a, b, c):
   
  vertex=(((-b / (2 * a)),(((4 * a * c) - (b * b)) / (4 * a))))
  return vertex
def parabola_vertex(a, b, c):
   
  vertex=(((-b / (2 / a)),(((4 * a * c) - (b * b)) / (4 * a))))
  return vertex