1. Find an equation for the surface consisting of all points that are equidistant from the point (0, -4, 0) and the plane y = 2. 2. Find an equation for and classify the surface consisting of all points such that the sum of the distances from the fixed points (6,0,0) and (-6,0,0) is 20. 3. Find an equation for and classify the surface consisting of all points such that the difference of the distances from the fixed points (13, 0, 0) and (-13,0,0) is 10. 4. Determine the center of mass of the first quadrant region inside the curve by x+y = 6y and above the line y = 3. [ 5. Evaluate the integral x(x-9) (3 -x) dx.