document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=108238>Question 108238</A>: <I><SPAN STYLE=\"word-break: break-all;\"> daughter needs help, and so do i apparently,  sure would like to know the procedure for solving this:   8y+5z=4390<BR>\n" );
document.write( "                               y+z= 680  ,  any help is more that appreciated, <BR>\n" );
document.write( "thanx   phil </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #78853 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=78853\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 8y+5z=4390<BR>\n" );
document.write( " y+z = 680  <BR>\n" );
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document.write( "This pair of equations is called a \"system\" of equations.<BR>\n" );
document.write( "We are looking for a pair of numbers that can replace <BR>\n" );
document.write( "y and z and will make both eqations true.<BR>\n" );
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document.write( "One way to \"solve\" a system like this is called substitution.<BR>\n" );
document.write( "The 2nd equation can be written as follows: y = 680-z<BR>\n" );
document.write( "------------<BR>\n" );
document.write( "Substitute this value of \"y\" for y in the 1st equation to get:<BR>\n" );
document.write( "8(680-z)+5z=4390<BR>\n" );
document.write( "5440-8z+5z = 4390<BR>\n" );
document.write( "-3z = -1050<BR>\n" );
document.write( "z = 350<BR>\n" );
document.write( "-----------<BR>\n" );
document.write( "Now substitute that value into y = 680-z to solve for \"y\".<BR>\n" );
document.write( "y = 680-350 = 330<BR>\n" );
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document.write( "Check this solution in the original equations:<BR>\n" );
document.write( "8y+5z=4390<BR>\n" );
document.write( "  y+z= 680 <BR>\n" );
document.write( "--------<BR>\n" );
document.write( "350+330= 680<BR>\n" );
document.write( "That's true<BR>\n" );
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document.write( "8*330+5*350 = 4390<BR>\n" );
document.write( "That's true<BR>\n" );
document.write( "--------<BR>\n" );
document.write( "So the solution is y=330 and z=350<BR>\n" );
document.write( "===================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );