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average

by baller12q » Sun Mar 29, 2009 12:14 pm
Which of the following is equal to the average of (x+2)^2 and (x-2)^2

a. x^2
b. x^2+2
c. x^2+4
d. x^2+2x
e. x^2+4x


i dont understand
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by moutar » Sun Mar 29, 2009 2:37 pm
Average = ((x+2)^2 + (x-2)^2) / 2
= (x^2 + 4x + 4 + x^2 - 4x + 4)/2
= (2x^2 + 8) / 2
= x^2 + 4

Answer is C
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