Respuesta :

f(x) = -(x2+x-72)
y = -(x - 8)(x + 9)
the solutions are x = 8, -9; so the parabola is upside down (umbrella) crossing the x at 8 and -9, meaning that -9 + 8 = -1/2 = -0.5 is where the focus is, or x = -0.5 as the axis of symmetry