document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=430834>Question 430834</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm trying to help my niece with an algebra problem that has both of us stumped...\r<BR>\n" );
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document.write( "(s+t)(s-t)(s+t)(s-t)\r<BR>\n" );
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document.write( "The answer provided in her book is:\r<BR>\n" );
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document.write( "s^4-2t^2s^2t^2\r<BR>\n" );
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document.write( "I can't even get close to this answer.  I got the s^4 and think I got the s^2 and t^2, but I can't figure out the -2t^2.\r<BR>\n" );
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document.write( "If you can tell me what I'm doing wrong, I'd appreciate it.  \r<BR>\n" );
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document.write( "I came up with:\r<BR>\n" );
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document.write( "(s)(s)(s)(s) = s^4\r<BR>\n" );
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document.write( "(t)(-t)(t)(-t) = t^2\r<BR>\n" );
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document.write( "I am so confused right now, I don't know what to do.  It's been years since I had Algebra.\r<BR>\n" );
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document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #299124 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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/cgi-bin/show-face.mpl?user=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=299124\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In identities there is a formula for the product of sum and difference of two variables.\r<BR>\n" );
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document.write( "(a+b)(a-b)=a^2-b^2\r<BR>\n" );
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document.write( "(s+t)(s-t)(s+t)(s-t)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28s%5E2-t%5E2%29%28s%2Bt%29%28s-t%29 ALIGN=MIDDLE  ALT=\"%28s%5E2-t%5E2%29%28s%2Bt%29%28s-t%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28s%5E2-t%5E2%29%28s%5E2-t%5E2%29 ALIGN=MIDDLE  ALT=\"%28s%5E2-t%5E2%29%28s%5E2-t%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28s%5E2-t%5E2%29%5E2 ALIGN=MIDDLE  ALT=\"%28s%5E2-t%5E2%29%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Another formula is (a-b)^2= a^2-2ab+b^2<BR>\n" );
document.write( "here a= s^2 & b=t^2<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s%5E4-2s%5E2t%5E2%2Bt%5E4 ALIGN=MIDDLE  ALT=\"s%5E4-2s%5E2t%5E2%2Bt%5E4\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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