document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=737121>Question 737121</A>: <I><SPAN STYLE=\"word-break: break-all;\"> (a)(b)+(-a)(b)+(b)(-a)-(a)(b)-(-a)(-b)<BR>\n" );
document.write( "How do I solve this or what is the answer? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #450175 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39620)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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=450175\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-c ALIGN=MIDDLE  ALT=\"-c\"   DISABLED_style= \"max-width:90%; height:auto;\" > is another way of expressing <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28-1%29%2Ac ALIGN=MIDDLE  ALT=\"%28-1%29%2Ac\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "A basic law of real numbers is  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c%2B%28-c%29=0 ALIGN=MIDDLE  ALT=\"c%2B%28-c%29=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "For two real numbers a and b, a-b means the same thing as a+ (-b).\r<BR>\n" );
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document.write( "Review those facts for a few minutes and try.... understand them.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28a%29%28b%29%2B%28-a%29%28b%29%2B%28b%29%28-a%29-%28a%29%28b%29-%28-a%29%28-b%29=ab-ab-ab-ab-ab ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >, can you see how?<BR>\n" );
document.write( "=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ab%2B%28-ab%29%2B%28-ab%29%2B%28-ab%29%2B%28-ab%29 ALIGN=MIDDLE  ALT=\"ab%2B%28-ab%29%2B%28-ab%29%2B%28-ab%29%2B%28-ab%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, but do you know why I show it this way?<BR>\n" );
document.write( "=.<BR>\n" );
document.write( "=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-3ab ALIGN=MIDDLE  ALT=\"-3ab\"   DISABLED_style= \"max-width:90%; height:auto;\" >, Excuse me for skipping a step or two.\r<BR>\n" );
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document.write( "post-note:  There are a couple of ways to go from the step just before the \"=.\" line.  The more pathways are shown, the more confusing a solution can be for a student.  What may be best if a step is missing is for the student to try to fill in any missing steps.  Knowing exactly which steps a student needs and which would be distracting is often not possible.  Direct interaction is a better situation sometimes than sending and reading text & symbols messages.<BR>\n" );
document.write( "One suggestion for the step at the \"=.\" line is to use the additive inverse concept, like for some number c,  we can be assured of c+(-c)=0.  The number, c, may stand for any real number, like r, or uw, or xwp, or ab...  </SPAN>\n" );
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