Avg = [(x+1)^2 + (x-1)^2] / 2
Expanding and simplifying, (x^2 + 2x + 1 + x^2 -2x + 1 ) / 2 = x^2 + 1
Which of the following is equal to the average (arithmetic mean) of (x+1)^2 and (x-1)^2?
a) x^2
b) x^2+1
c) x^2 +4
d) x^2+2x
e) x^2+4x