document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=691827>Question 691827</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve each system by substitution. Show your work.<BR>\n" );
document.write( "1) a= 3b+1<BR>\n" );
document.write( "    5a-3b= 13\r<BR>\n" );
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document.write( "2) 4y= -3x<BR>\n" );
document.write( "     5x+8y= 4\r<BR>\n" );
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document.write( "3) y= 2x<BR>\n" );
document.write( "   x+y= 21\r<BR>\n" );
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document.write( "4) r= -3s<BR>\n" );
document.write( "    3r+ 4s= -10\r<BR>\n" );
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document.write( "5) y= x+3<BR>\n" );
document.write( "    3x+ 2y= 26\r<BR>\n" );
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document.write( "6) a+b= 11<BR>\n" );
document.write( "    3a-2b= 8\r<BR>\n" );
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document.write( "7) 7x-3y= 23<BR>\n" );
document.write( "    x+2y= 13\r<BR>\n" );
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document.write( "8) 2x+3y= 7<BR>\n" );
document.write( "    4x-5y= 25 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #426873 by </B><A HREF=/tutors/aboutme.mpl?userid=Edwin+McCravy><B>Edwin McCravy(20054)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Edwin+McCravy><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=Edwin+McCravy><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=426873\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\">\r\n" );
document.write( "I'll just do 5 and 8 for you:\r\n" );
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document.write( "5) y= x+3\r\n" );
document.write( " 3x+ 2y= 26 \r\n" );
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document.write( "Copy the second equation, but instead of y, don't \r\n" );
document.write( "write y, but instead write what y equals from the\r\n" );
document.write( "first equation, which is x+3 in parentheses (x+3)\r\n" );
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document.write( " 3x+ 2(x+3)= 26\r\n" );
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document.write( "Remove parentheses by distributing\r\n" );
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document.write( " 3x + 2x + 6 = 26\r\n" );
document.write( "      5x + 6 = 26\r\n" );
document.write( "          5x = 20\r\n" );
document.write( "           x = 4\r\n" );
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document.write( "Substitute (4) for x in y= x+3\r\n" );
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document.write( "           y= 4+3\r\n" );
document.write( "           y = 7\r\n" );
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document.write( "Solution: (x,y) = (4,7)\r\n" );
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document.write( "----------------------------\r\n" );
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document.write( "8) 2x+3y= 7\r\n" );
document.write( " 4x-5y= 25\r\n" );
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document.write( "We notice that the second equation has 4x and the first\r\n" );
document.write( "equation has 2x, and we know that 4x is 2 times 2x\r\n" );
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document.write( "So we solve the first equation for 2x\r\n" );
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document.write( "   2x+3y= 7\r\n" );
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document.write( "We subtract 3y from both sides\r\n" );
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document.write( "      2x= 7-3y\r\n" );
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document.write( "We need 4x, not 2x, to substitute in the second equation,\r\n" );
document.write( "so we multiply both sides, every term, of that equation by 2:\r\n" );
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document.write( "      4x= 14-6y\r\n" );
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document.write( "Copy the second equation,  4x-5y= 25 but instead of 4x, \r\n" );
document.write( "don't write 4x, but instead write what 4x equals from that\r\n" );
document.write( "equation, which is 14-6y.\r\n" );
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document.write( "      14-6y-5y= 25\r\n" );
document.write( "Combine like terms\r\n" );
document.write( "        14-11y = 25 \r\n" );
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document.write( "Add -14 to both sides:\r\n" );
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document.write( "          -11y = 11\r\n" );
document.write( "             y = -1\r\n" );
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document.write( "Solution: (x,y) = (5,-1)\r\n" );
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document.write( "Edwin</PRE>\r<BR>\n" );
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document.write( " </SPAN>\n" );
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