document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1636>Question 1636</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sum of two digits of a two digit number is seven. If the digits are reversed, the new number is nine less than the original number. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #2048 by </B><A HREF=/tutors/aboutme.mpl?userid=rapaljer><B>rapaljer(4671)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rapaljer><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=rapaljer><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=2048\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let  t = tens digit<BR>\n" );
document.write( "     u = units digit\r<BR>\n" );
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document.write( "The value of the original number is ten times the tens digit plus the units digit.  That is, 10 t + u.\r<BR>\n" );
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document.write( "If the digits are reversed, then u becomes the tens digit, and t becomes the units digit, and the value of the number is 10u + t.\r<BR>\n" );
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document.write( "Since there are two variables, you need to find two equations.\r<BR>\n" );
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document.write( "\"The sum of the digits is seven.\"<BR>\n" );
document.write( "t + u = 7\r<BR>\n" );
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document.write( "\"If digits are reversed, the new number is nine less than the original.\"<BR>\n" );
document.write( "10u + t = 10t + u - 9.  \r<BR>\n" );
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document.write( "Simplify this equation by subtracting 10t and u from each side of the equation.<BR>\n" );
document.write( "10u + t - 10t - u = -9   \r<BR>\n" );
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document.write( "Simplify this equation and divide both sides of the resulting equation by 9:<BR>\n" );
document.write( "-9t + 9u = -9   <BR>\n" );
document.write( "-t + u = -1\r<BR>\n" );
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document.write( "Now you have two equations that you can add together:<BR>\n" );
document.write( "t + u = 7<BR>\n" );
document.write( "-t + u = -1\r<BR>\n" );
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document.write( "2u = 6<BR>\n" );
document.write( "u = 3\r<BR>\n" );
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document.write( "Since the sum of the digits is 7, that makes t = 4.<BR>\n" );
document.write( "The original number is 43, and the new number, with digits reversed, is 34.  \r<BR>\n" );
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document.write( "Check:  When the digits are reversed, the new number is indeed 9 less than the original number.\r<BR>\n" );
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document.write( "R^2 at SCC\r<BR>\n" );
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