6. The bulb in a lamp with parabolic reflector is placed at the focus, and the focal diameter is 12 cm. Find an equation of the parabola, and the size of the opening 20 cm away from the vertex. 7. Pluto's orbit is the most eccentric in the solar system with eccentricity 0.25. The length of the minor axis of its orbit is approximately 10,000,000,000 km. Find the distance between Pluto and the sun when it is closest to and farthest from the sun