mean

[vladmire]

Should I plug a number into the variable x? solve and then divide by 2 and do the same for each answer choice?

[cramya]

(x+2)^2 = x^2+4+4x

(x-2)^2 = x^2+4-4x

Average = (x+2)^2 + (x-2)^2 / 2

= x^2+4+4x + x^2+4-4x / 2

= 2x^2+8/2
= 2(x^2+4) / 2

= x^2+4

[kris610]

Vlad, while posting questions from the GMATPrep, can you please mention that in the subject of the post!

[vishubn]

Should I plug a number into the variable x? solve and then divide by 2 and do the same for each answer choice?

plugging will take more time than solving algebraically ! at least for this problem it holds good

the formula u required to know is simple so rather sole it than plugging in

Vishu