Calculate-the-sum-of-2-x-2-x-if-4-x-4-x-23-

Question Number 4413 by alib last updated on 22/Jan/16

C alculate the sum of 2^{x} + 2^{- x},

if 4^{x} + 4^{- x} = 23

Answered by prakash jain last updated on 22/Jan/16

{(2^{x} + 2^{- x})}^{2} = 4^{x} + 4^{- x} + 2 = 25

2^{x} + 2^{- x} = 5