Classify each of the following quadric surfaces as either an ellipsoid, hyperboloid of one sheet, hyperboloid of two sheets, elliptic cone, elliptic paraboloid, or hyperbolic paraboloid. Record the values of a, b, and c for each quadric surface. a) 2z - x^2-4y^2=0
b) 6x^2+3y^2+4z^2=12
c)4x^2+y^2-4z^2=-4
d)y^2-x^2-z=0
e) 9x^2+y^2-9z^2=9
f) 12z^2-3x^2=4y^2​