Which of the following is equal to the average (arithmetic mean) of (y+4)^2 and (y-4)^2?
Options:
(A) x^2
(B) x^2+2
(C) x^2 +12
(D) x^2+21
(E) y^2+16 Stream of consciousness first, then make a decision:
Avg = [(y+4)^2 + (y-4)^2] / 2
Expanding and simplifying, (y^2 + 8y + 16 + y^2 - 8y + 16 ) / 2 = y^2 + 16
Thus, the answer is (E).