For example, a= 1, b=2 and c=3 satisfy AB 2.
A=2, b= 1, c=-3 satisfies a+b+c=0, but does not satisfy ab 2.
(2) It is neither a sufficient condition nor a necessary condition.
For example, a=-3, b=2, c= 1 satisfies AB 2.
A=-3, b=0, c= 1 satisfies a.