Which of the following is equal to the average (arithmetic mean) of (y+4)^2 and (y-4)^2?  Answers.
A) x^2 B) x^2+2 C) x^2 +12 D) x^2+21 E) y^2+16
Avg = [(y+4)^2 + (y-4)^2] / 2   y^2+16xpanding and simplifying, (y^2 + 8y + 16 + y^2 - 8y + 16 ) / 2 = y^2 + 16   Answer y^2+16.
<result>E</result>
Which of the following is equal to the average (arithmetic mean) of (y+4)^2 and (y-4)^2?