Question 825824
-3 to the -4 power? 

{{{(-3)^(-4)}}}
{{{1/(-3)^4}}}
{{{1/((9)(9))}}}
{{{1/81}}}


How your notation appears on paper might help in understanding why your teacher judged your answer as wrong.  If your process included what you showed in your posting, {{{-3x-3x-3x-3= 81}}}, then yes, your work is wrong and your answer, whether right or wrong, is still wrong.