Which of the following is equal to the average (arithmetic mean) of (x+5)^2 and (x-5)^2?  Choose the correct option
A) x^2 B) x^2+2 C) x^2 +30 D) x^2+20 E) x^2+25
Avg = [(x+5)^2 + (x-5)^2] / 2   x^2+25xpanding and simplifying, (x^2 + 10x + 25 + x^2 - 10x + 25) / 2 = x^2 + 25   Answer x^2+25.
<result>E</result>
Which of the following is equal to the average (arithmetic mean) of (x+5)^2 and (x-5)^2?