3. Calculate the distance between the points: (a) (5 points) A(3, 4, 2) and B(-1, 6, -2) (b) (5 points) P(-1, 5, 0) and Q(1, 3, 2). 4. (5 points) The center of a sphere is (4, 3, 5) and its radius is r = 3 units. Find the equation for the sphere. 5. (5 points) The equation of a sphere is (z + 2)? + y + (z-4)2 - 25. Find the center C(z, y, z) and the radius r