document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=217213>Question 217213</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The length of a rectangle is 4in longer than its width. If the perimeter of the rectangle is 28in, find its area.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #163811 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=163811\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Keep in mind that perimeter is 2*length plus 2*width.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28+length+=+width%2B4%2C+2%2Alength%2B2%2Awidth+=+28+%29+ ALIGN=MIDDLE  ALT=\"system%28+length+=+width%2B4%2C+2%2Alength%2B2%2Awidth+=+28+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "This is a linear system: \r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28+length+-width+=+4%2C+2%2Alength%2B2%2Awidth+=+28+%29+ ALIGN=MIDDLE  ALT=\"system%28+length+-width+=+4%2C+2%2Alength%2B2%2Awidth+=+28+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "which you can solve with the linear solver\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%5Clength+%2B+-1%5Cwidth+=+4%2C%0D%0A++++2%5Clength+%2B+2%5Cwidth+=+28+%29%0D%0A++ ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >We'll use substitution. After moving -1*width to the right, we get:<BR>\n" );
document.write( "  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2Alength+=+4+-+-1%2Awidth ALIGN=MIDDLE  ALT=\"1%2Alength+=+4+-+-1%2Awidth\"   DISABLED_style= \"max-width:90%; height:auto;\" >, or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=length+=+4%2F1+-+-1%2Awidth%2F1 ALIGN=MIDDLE  ALT=\"length+=+4%2F1+-+-1%2Awidth%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=2%2A%284%2F1+-+-1%2Awidth%2F1%29+%2B+2%5Cwidth+=+28 ALIGN=MIDDLE  ALT=\"2%2A%284%2F1+-+-1%2Awidth%2F1%29+%2B+2%5Cwidth+=+28\"   DISABLED_style= \"max-width:90%; height:auto;\" > and simplify: So, we know that width=5. Since <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=length+=+4%2F1+-+-1%2Awidth%2F1 ALIGN=MIDDLE  ALT=\"length+=+4%2F1+-+-1%2Awidth%2F1\"   DISABLED_style= \"max-width:90%; height:auto;\" >, length=9.<BR>\n" );
document.write( "  <BR>\n" );
document.write( "  Answer: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28+length=9%2C+width=5+%29 ALIGN=MIDDLE  ALT=\"system%28+length=9%2C+width=5+%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
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