Derive the equation of the parabola with a focus at (? 5, ? 5) and a directrix of y = 7. f(x) = ? one twenty fourth(x ? 1)2 ? 5 f(x) = one twenty fourth(x ? 1)2 ? 5 f(x) = ? one twenty fourth(x + 5)2 + 1 f(x) = one twenty fourth(x + 5)2 + 1