Question 521177
{{{9x^4-81y^2}}}



{{{9(x^4-9y^2)}}}



{{{9((x^2)^2-(3y)^2)}}}



{{{9(x^2-3y)(x^2+3y)}}} Use the difference of squares factoring formula here.



So {{{9x^4-81y^2}}} factors to {{{9(x^2-3y)(x^2+3y)}}} 



In other words, {{{9x^4-81y^2=9(x^2-3y)(x^2+3y)}}} 


If you need more help, email me at <a href="mailto:jim_thompson5910@hotmail.com">jim_thompson5910@hotmail.com</a>


Also, please consider visiting my website: <a href="http://www.freewebs.com/jimthompson5910/home.html">http://www.freewebs.com/jimthompson5910/home.html</a> and making a donation. Thank you


Jim