document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=78705>Question 78705</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Factor completely<BR>\n" );
document.write( "9x^2 + 24xy - 9y^2<BR>\n" );
document.write( "I know the GCF is 3, but I don't know what to do with the two different variables. Thank you </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #56433 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=56433\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Factor completely<BR>\n" );
document.write( "9x^2 + 24xy - 9y^2<BR>\n" );
document.write( "=3(3x^2+8xy-3y^2)<BR>\n" );
document.write( "Think of two numbers whose product is 3*-3=-9 and whose sum is 8<BR>\n" );
document.write( "The numbers are +9 and -1<BR>\n" );
document.write( "So rewrite the problem putting 9xy-1xy in place of 8xy<BR>\n" );
document.write( "=3(3x^2+9xy-xy-3y^2)<BR>\n" );
document.write( "Factor the 1st two and the last two terms separately to get:<BR>\n" );
document.write( "=3(3x(x+3y)-y(x+3y))<BR>\n" );
document.write( "Factor out the common factor to get:<BR>\n" );
document.write( "=3(x+3y)(3x-y)<BR>\n" );
document.write( "===========<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );