Answers

2014-05-28T20:09:54+08:00
4^x + 4^(-x) = 9
2^2x + 2^(-2x) = 9
2^2x + 2 + 2^(-2x) = 9 + 2
(2^x + 2^(-x)) ^2= 11
2^x +2^(-x) = sqrt(11)



8^x + 8^(-x) = ?
2^3x + 2^(-3x) = ?
(2^x + 2^(-x))(2^2x - 1 + 2^(-2x))=?
(sqrt(11))(9-1)=?
(sqrt(11))(8) = ?

=8sqrt(11)

Well..... I hope I'm right... haha :)

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