document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=7246>Question 7246</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Erin's age is 3 times Warren's.  In 4 years she will be twice as old as he will be.  how old is each now? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #4009 by </B><A HREF=/tutors/aboutme.mpl?userid=ichudov><B>ichudov(507)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ichudov><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=ichudov><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=4009\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Translation from English into algebrese:\r<BR>\n" );
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document.write( "Erin   = 3*Warren<BR>\n" );
document.write( "Erin+4 = 2*(Warren+4)\r<BR>\n" );
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document.write( "Erin-3*Warren   = 0<BR>\n" );
document.write( "Erin - 2*Warren = 4\r<BR>\n" );
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document.write( " <TR><TD  ALIGN=MIDDLE>Solved by <A  rel=nofollow HREF=http://wiki.algebra.com/index.php/Tutoring_-_pluggable_solvers>pluggable</A> solver: <A  rel=nofollow HREF=linear_substitution.solver>SOLVE linear system by SUBSTITUTION</A></TD></TR>\n" );
document.write( "<TR><TD  ALIGN=LEFT>Solve:<BR>\n" );
document.write( "  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+system%28+%0D%0A++++1%5CErin+%2B+-3%5CWarren+=+0%2C%0D%0A++++1%5CErin+%2B+-2%5CWarren+=+4+%29%0D%0A++ ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >We'll use substitution. After moving -3*Warren to the right, we get:<BR>\n" );
document.write( "  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2AErin+=+0+-+-3%2AWarren ALIGN=MIDDLE  ALT=\"1%2AErin+=+0+-+-3%2AWarren\"   DISABLED_style= \"max-width:90%; height:auto;\" >, or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Erin+=+0%2F1+-+-3%2AWarren%2F1 ALIGN=MIDDLE  ALT=\"Erin+=+0%2F1+-+-3%2AWarren%2F1\"   DISABLED_style= \"max-width:90%; height:auto;\" >. Substitute that<BR>\n" );
document.write( "  into another equation:<BR>\n" );
document.write( "  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2A%280%2F1+-+-3%2AWarren%2F1%29+%2B+-2%5CWarren+=+4 ALIGN=MIDDLE  ALT=\"1%2A%280%2F1+-+-3%2AWarren%2F1%29+%2B+-2%5CWarren+=+4\"   DISABLED_style= \"max-width:90%; height:auto;\" > and simplify: So, we know that Warren=4. Since <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Erin+=+0%2F1+-+-3%2AWarren%2F1 ALIGN=MIDDLE  ALT=\"Erin+=+0%2F1+-+-3%2AWarren%2F1\"   DISABLED_style= \"max-width:90%; height:auto;\" >, Erin=12.<BR>\n" );
document.write( "  <BR>\n" );
document.write( "  Answer: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28+Erin=12%2C+Warren=4+%29 ALIGN=MIDDLE  ALT=\"system%28+Erin=12%2C+Warren=4+%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "  </TD></TR>\n" );
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document.write( " </SPAN>\n" );
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