The derivation for the equation of a parabola with a vertex at the origin is started below. = (x)2 + (y – p)2 = (0)2 + (y + p)2 x2 + y2 – 2py + p2 = y2 + 2py + p2 if the equation is further simplified, which equation for a parabola does it become? x2 = 4py x2 = 2y2 + 2p2 y2 = 4px y2 = 4py