document.write( "Question 201273This question is from textbook college algebra
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solve the system analytically: \r\n" );
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document.write( " x +  y +  z = 10\r\n" );
document.write( "2x + 6y + 2z = 40\r\n" );
document.write( "-x + 7y - 3z = 26
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Algebra.Com's Answer #151502 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
Solve the system analytically: \r\n" );
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document.write( " x +  y +  z = 10\r\n" );
document.write( "2x + 6y + 2z = 40\r\n" );
document.write( "-x + 7y - 3z = 26\r\n" );
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document.write( "1.  Pick two equation and a letter to eliminate\r\n" );
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document.write( "I will pick equations 1 and 3 and x to eliminate\r\n" );
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document.write( " x +  y +  z = 10\r\n" );
document.write( "-x + 7y - 3z = 26\r\n" );
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document.write( "If you just add them as they are, the x's will be\r\n" );
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document.write( " x +  y +  z = 10\r\n" );
document.write( "-x + 7y - 3z = 26\r\n" );
document.write( "-----------------\r\n" );
document.write( "     8y - 2z = 36\r\n" );
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document.write( "2.  Pick a different pair of equation and the SAME\r\n" );
document.write( "    letter to eliminate.  (You must pick one equation\r\n" );
document.write( "    the same as before but pick the other of them \r\n" );
document.write( "    different \r\n" );
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document.write( "I will pick equations 1 and 2 and eliminate x\r\n" );
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document.write( " x +  y +  z = 10\r\n" );
document.write( "2x + 6y + 2z = 40\r\n" );
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document.write( "If you multiply the first through by -2, the x's \r\n" );
document.write( "will be eliminated when you add them:\r\n" );
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document.write( "-2x - 2y - 2z = -20\r\n" );
document.write( " 2x + 6y + 2z =  40\r\n" );
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document.write( "      4y      =  20\r\n" );
document.write( "            y =   5 \r\n" );
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document.write( "3.  Solve the system:\r\n" );
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document.write( "     \r\n" );
document.write( "     8y - 2z = 36\r\n" );
document.write( "           y =  5\r\n" );
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document.write( "Substitute:\r\n" );
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document.write( "   8(5) - 2z = 36\r\n" );
document.write( "     40 - 2z = 36\r\n" );
document.write( "         -2z = -4\r\n" );
document.write( "           z = 2\r\n" );
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document.write( "Substitute y = 5 and z = 2 in the\r\n" );
document.write( "first original equation:\r\n" );
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document.write( "      x + y + z = 10\r\n" );
document.write( "      x + 2 + 5 = 10\r\n" );
document.write( "          x + 7 = 10\r\n" );
document.write( "              x = 3\r\n" );
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document.write( "So the solution is (x,y,z) = (3,5,2)\r\n" );
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document.write( "Edwin
 
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