document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=81452>Question 81452</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve the system by substitution.<BR>\n" );
document.write( "     3x – y = –7<BR>\n" );
document.write( "       x + y = –9<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #58358 by </B><A HREF=/tutors/aboutme.mpl?userid=mathdoc316><B>mathdoc316(9)</B></A><img src=\"/images/stars/stars-05.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mathdoc316><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=58358\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Step 1: Isolate one variable, using one of the equations<BR>\n" );
document.write( "Step 2: Substitute that into the other equation to eliminate the variable<BR>\n" );
document.write( "Step 3: Solve that resulting equation for the remaining variable<BR>\n" );
document.write( "Step 4: Solve for the variable that was eliminated<BR>\n" );
document.write( "Step 5: Check the solution\r<BR>\n" );
document.write( "\n" );
document.write( "Step 1 will be easy here if we use the 2nd equation, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2By=-9 ALIGN=MIDDLE  ALT=\"x%2By=-9\"   DISABLED_style= \"max-width:90%; height:auto;\" >, to isolate a variable.  It could easily be x or y.  Let's just do x since it doesn't matter that much.\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-9-y ALIGN=MIDDLE  ALT=\"x+=+-9-y\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "Step 2: Substitute that expression for x into the first equation<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3x+-+y+=+-7 ALIGN=MIDDLE  ALT=\"3x+-+y+=+-7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-9-y ALIGN=MIDDLE  ALT=\"x+=+-9-y\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3+%2A+%28-9-y%29+-+y+=+-7 ALIGN=MIDDLE  ALT=\"3+%2A+%28-9-y%29+-+y+=+-7\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "Step 3: Simplify and solve for y<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-27+-+3y+-+y+=+-7 ALIGN=MIDDLE  ALT=\"+-27+-+3y+-+y+=+-7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-27+-+4y+=+-7+ ALIGN=MIDDLE  ALT=\"+-27+-+4y+=+-7+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Add 27 to both sides<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-4y+=+20+ ALIGN=MIDDLE  ALT=\"+-4y+=+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Divide both sides by -4<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+y+=+-5+ ALIGN=MIDDLE  ALT=\"+y+=+-5+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "Step 4: Find x<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+-9+-+y ALIGN=MIDDLE  ALT=\"+x+=+-9+-+y\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+-9+-+%28-5%29+=+-4+ ALIGN=MIDDLE  ALT=\"+x+=+-9+-+%28-5%29+=+-4+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "Step 5: Check the solution<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+-4 ALIGN=MIDDLE  ALT=\"+x+=+-4\"   DISABLED_style= \"max-width:90%; height:auto;\" >, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+-5+ ALIGN=MIDDLE  ALT=\"y+=+-5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3%2Ax+-+y+=+-7+ ALIGN=MIDDLE  ALT=\"+3%2Ax+-+y+=+-7+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+%2B+y+=+-9+ ALIGN=MIDDLE  ALT=\"+x+%2B+y+=+-9+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3+%2A+-4+-+%28-5%29+=+-12+%2B+5+=+-7+ ALIGN=MIDDLE  ALT=\"+3+%2A+-4+-+%28-5%29+=+-12+%2B+5+=+-7+\"   DISABLED_style= \"max-width:90%; height:auto;\" > YES <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+%2B+y+=+-4+%2B+%28-5%29+=+-9+ ALIGN=MIDDLE  ALT=\"x+%2B+y+=+-4+%2B+%28-5%29+=+-9+\"   DISABLED_style= \"max-width:90%; height:auto;\" > YES <BR>\n" );
document.write( "The solution is correct\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
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