$3^{x-1}+3^{x-2}+3^{x-3}=3159$
Another exponential equation I'm having a hard time with, the answer is given and equals to : $8$. I'm absolutely sure I'm making a wrong step somewhere along the way. Any help is appreciated.
EDIT:
$3^{x-3}(\frac{1}{8}+\frac{1}{243}+1)=3159$
This is where I'm now. If this is correct, it should pretty simple from here on. But I just don't seem to reach 8 as the final answer.