For which values a, b, c is S: a regular surface, a regular curve, a set of points, the empty set? Let: S = {(x, y, z) : ax + by? + cz? = 0, a2 + y? + 2 = 1} %3D Hint: Consider the cases where some of the a, b, c are zero and others non-zero. In the cases where they are non-zero, consider the cases where they have the same sign and the cases where they have opposite sign