document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=243094>Question 243094</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help setting up this problem. \r<BR>\n" );
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document.write( "The sum of a certain number and a second number is 21.<BR>\n" );
document.write( "The second number minus the first number is -57.<BR>\n" );
document.write( "Use a system of two equations with two variables to find the numbers. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #178106 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><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=178106\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The sum of two numbers is 21:<BR>\n" );
document.write( "x + y = 21<BR>\n" );
document.write( "This means we can show y = 21 - x.<BR>\n" );
document.write( "...<BR>\n" );
document.write( "The second number minus the first number is -57.<BR>\n" );
document.write( "y - x = -57<BR>\n" );
document.write( "...<BR>\n" );
document.write( "Substituting 21-x for y, we have<BR>\n" );
document.write( "21-x -x = -57<BR>\n" );
document.write( "21 - 2x = -57<BR>\n" );
document.write( "Adding 2x to both sides<BR>\n" );
document.write( "21 = -57 +2x<BR>\n" );
document.write( "Adding 57 to both sides<BR>\n" );
document.write( "21 + 57 = 2x<BR>\n" );
document.write( "78 = 2x<BR>\n" );
document.write( "Dividing by 2<BR>\n" );
document.write( "39 = x<BR>\n" );
document.write( "...<BR>\n" );
document.write( "x + y = 21<BR>\n" );
document.write( "x = 39<BR>\n" );
document.write( "29 + y = 21<BR>\n" );
document.write( "So, y = -18<BR>\n" );
document.write( "...<BR>\n" );
document.write( "Checking our work, does the second number minus the first number = -57?<BR>\n" );
document.write( "-18 -39 = -57.<BR>\n" );
document.write( "Done. </SPAN>\n" );
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