Suppose A and B are square matrices of the same size. Which of the following are NOT necessarily true? (AB)= A B (A+B)(AB) = A - B (A+B)= A + 2AB+ B (A+B) = A3+ B == OA B = A(AB)B (A+B)= A2 + AB + BA + B (A-B)= A-2AB+ B