How do I solve this exponential function problem?

[Linty Fresh]

I'm just starting exponential functions, and I'm doing OK except for one or two things.

Like this:

If 2^x=3, what does 4^-x equal?

I think it's 1/9

4^-x = 2^-2x, take three, square it, and find the reciprocal.

Am I doing this right?

Thanks.

 

[tkhunny]

You have it!