Moj, there are different routes you can take. One would be symbolic
syms A B C D E F x y z
sol = solve(A*x^2+B*y^2+C*z^2+2*D*x*y+2*E*x*z+2*F*y*z-1==0, z);
sol1 = subs(sol(1),{A,B,C,D,E,F},{1,2,3,4,5,6});
sol2 = subs(sol(2),{A,B,C,D,E,F},{1,2,3,4,5,6});
ezsurf(sol1)
hold on
ezsurf(sol2)
The hold command allows you to add several plots in the same figure.
