3.5.13 Surfaces of the 2-DD Order

Condition: Build surfaces of the second order: a) \ (z^{2} = 4-2 x \) \ (x^{2}+z^{2} = 4+2 y \) c) \ (9 x^{2}+y^{2} -z^{2} = 0 \); d) \ (x^{2}+y^{2} +6 y+z^{2} -2 z = 0 \).