Which of the following is equal to the average (arithmetic mean) of (x+3)^2 and (x-3)^2?
Choose the correct choice from the following answers:	A) x^2	B) x^2+2	C) x^2 +4	D) x^2+9	E) x^2+4x
Avg = [(x+3)^2 + (x-3)^2] / 2   Expanding and simplifying, (x^2 + 6x + 9 + x^2 - 6x + 9 ) / 2 = x^2 + 9   Answer x^2+9.
<result>D</result>
Which of the following is equal to the average (arithmetic mean) of (x+3)^2 and (x-3)^2?