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 :)
