+69 Let a, b, c, and d be real numbers such that a > b and c > d. Which of the below statements are true?
(A) a + c > b + d.
(B) 2a + 3c > 2b + 3d.
(C) a - c > b - d.
(D) ac > bd.
(E) a^2 + c^2 > b^2 + d^2.
(F) a^3 + c^3 > b^3 + d^3.
I got A, B, C, and F, but it's apparently not right. Can I get some help?
