Multiply both sides by :
Put all terms on one side:
If you let w = 2^x, then this looks like a quadratic:
Solve for w (using the quadratic formula is probably the easiest), but don't forget to replace w with 2^x afterwards and solve for x.
I need to solve this algebraically. I already know the answer, which is +/-2.2604 or (log(5/2 +/- (rt21)/2))/(log(2)). I just need to know HOW to get there.
2^x + 2^(-x) = 5
I tried solving it using factoring/quadratics, but couldn't figure out how to set it up.