document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=25717>Question 25717</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if a=b<BR>\n" );
document.write( "then<BR>\n" );
document.write( "a*a=a*b<BR>\n" );
document.write( "a^2=ab<BR>\n" );
document.write( "a^2-b^2=ab-b^2<BR>\n" );
document.write( "(a+b)(a-b)=b(a-b)<BR>\n" );
document.write( "a+b=b<BR>\n" );
document.write( "a+a=a<BR>\n" );
document.write( "2a=a<BR>\n" );
document.write( "it contradicts the assumption..<BR>\n" );
document.write( "what is wrong in this ? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #13820 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=13820\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> When you had (a+b)(a-b)=b(a-b) you divided both sides<BR>\n" );
document.write( "by (a-b) to get a+b=b.<BR>\n" );
document.write( "But in doing that you divided by zero because you <BR>\n" );
document.write( "started the argument by saying a=b.<BR>\n" );
document.write( "Dividing by zero is an illegal move, i.e. it is <BR>\n" );
document.write( "meaningless; so you ended up with a meaningless<BR>\n" );
document.write( "conclusion.\r<BR>\n" );
document.write( "\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );