Or at least I think I do...

These are the two problems I have:

#1: $\displaystyle 4^{4x}=2000; x=?$

#2: $\displaystyle 4log(x-4)=16; x=?$

...so I basically just need to know what $\displaystyle x$ equals, and just plugging in numbers isn't very practical :( Can anyone help?