With the help of the forum, I've gone through many more exponent exercises. But I have one more questions.

Problem with this one is that I do not know the answer, but I assume that the answer much be a simple whole number - all the other answers for this section are - but my solution doesn't seem to be right.

Problem

2^(x)+8*2^(-x)=9

I started out by multiplying both sides by 2^(x)... and simplified. I ended up with 20^x=18^x

any thoughts?!?