You can put this solution on YOUR website! use difference of two cubes (http://www.purplemath.com/modules/specfact2.htm)
Then look here for the answer
http://www.wolframalpha.com/input/?i=81s^6-3x^6
Here is another website that is good for factoring
http://72.3.253.76:8080/webMathematica3/quickmath/page.jsp?s1=algebra&s2=factor&s3=basic
Hope this helps