document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=114622>Question 114622</A>: <I><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "why is a negative number times a negative number equal to a positive number? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #83383 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=83383\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> why is a negative number times a negative number equal to a positive number?<BR>\n" );
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document.write( "There are a number of ways to describe this.<BR>\n" );
document.write( "Here is one:<BR>\n" );
document.write( "If a + -a = 0 and a = n(-m) you can write:<BR>\n" );
document.write( "n(-m)+-(n(-m)) = 0<BR>\n" );
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document.write( "But n(-m) = -nm<BR>\n" );
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document.write( "Substituting -mn for n(-m) you get:<BR>\n" );
document.write( "-nm + -(n(-m))= 0<BR>\n" );
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document.write( "Also -nm + nm = 0<BR>\n" );
document.write( "Therefore nm = -(n(-m))\r<BR>\n" );
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document.write( "You can also discribe the double negative geometrically.<BR>\n" );
document.write( "If 2 is two to the right on the number line<BR>\n" );
document.write( "and -2 is two to the left.<BR>\n" );
document.write( "The 2*-2 is two to the left twice.<BR>\n" );
document.write( "And -(2*-2) is the opposite of twice two to the left which is<BR>\n" );
document.write( "the same as two twice to the right.<BR>\n" );
document.write( "So, -2*-2 = 2*2<BR>\n" );
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document.write( "You can also describe it financially as the loss of a loss,<BR>\n" );
document.write( "which would be a gain.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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