document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=90831>Question 90831</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" );
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document.write( "    Solve the system by substitution.<BR>\n" );
document.write( "3x – y = –7<BR>\n" );
document.write( "x + y = –9\r<BR>\n" );
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document.write( "          x+y = -9   or y = -9-x........(1)\r<BR>\n" );
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document.write( "         3x - y = -7........(2) \r<BR>\n" );
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document.write( "          substituting  for y from (1)   in (2)\r<BR>\n" );
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document.write( "          3x - (-9-x) = -7\r<BR>\n" );
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document.write( "          3x+9+x = -7<BR>\n" );
document.write( "              4x = -7-9 = -16<BR>\n" );
document.write( "               x = -16/4 = -4 <BR>\n" );
document.write( "     substituting  for x  in (1) we get y = -9-(-4) = -9+4 = -5\r<BR>\n" );
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document.write( "       The required solution is x = -4, & y = -5 </SPAN>\n" );
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