I can't tell whether you meant

 

or 



because there are no parentheses to show which you meant.

-----------------------------------

If you meant



Just divide top and bottom by 3 and get
 

 


-----------------------------------

If you meant



Then reduce the fraction  to 



Then take individual square roots of numerator and denominator:







Write 27 as 9·3



Take individual square roots of 9 and 3





  

  



Now rationalize the denominator by multiplying by 





Multiply under the radicals in the bottom:



    <-- final answer in simplest radical form

Edwin