document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1178730>Question 1178730</A>: <I><SPAN STYLE=\"word-break: break-all;\"> My son is learning factoring polynomials and he has a question that he is confused about. Would appreciate your help in clarifying this.\r<BR>\n" );
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document.write( "During factoring we factor the negative sign of the leading coefficient so why is that not done when we factor a difference of squares like 81 - x^2?\r<BR>\n" );
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document.write( "If written in standard form it would be  - x^2 + 81. So why is this incorrect :\r<BR>\n" );
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document.write( "  81-x^2\r<BR>\n" );
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document.write( "  - x^2 + 81\r<BR>\n" );
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document.write( "- (  x^2 - 81)\r<BR>\n" );
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document.write( "- ( x + 9 ) ( x-9)\r<BR>\n" );
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document.write( "His teacher says the correct answer is ( 9 + x) ( 9-x) and NOT -(x+9)(x-9)\r<BR>\n" );
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document.write( "Would appreciate your help. 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 #808103 by </B><A HREF=/tutors/aboutme.mpl?userid=MathLover1><B>MathLover1(20850)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathLover1><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=MathLover1><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=808103\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=81+-+x%5E2 ALIGN=MIDDLE  ALT=\"81+-+x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9%5E2+-+x%5E2 ALIGN=MIDDLE  ALT=\"9%5E2+-+x%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" >........use a rule: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5E2-b%5E2=%28a-b%29%28a%2Bb%29 ALIGN=MIDDLE  ALT=\"a%5E2-b%5E2=%28a-b%29%28a%2Bb%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "in your case <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a=9 ALIGN=MIDDLE  ALT=\"a=9\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b=x ALIGN=MIDDLE  ALT=\"b=x\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "so, you will have\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=9-x%29%289%2Bx%29 ALIGN=MIDDLE  ALT=\"9-x%29%289%2Bx%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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