document.write( "Question 679648: need help solving linear equation in three variables using the elimination method.
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document.write( "-3x-2y+4z=-5
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document.write( "2x+5y-3z=3
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document.write( "4x-y+7z=15\r
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Algebra.Com's Answer #422033 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! They are trying to torment you here, the solutions are not integers!\r \n" ); document.write( "\n" ); document.write( "-3x -2y + 4z =-5 \n" ); document.write( " 2x + 5y - 3z = 3 \n" ); document.write( " 4x - y + 7z = 15 \n" ); document.write( ": \n" ); document.write( "Multiply the 1st equation by -1 and add \n" ); document.write( "3x + 2y - 4z = 5 \n" ); document.write( " 2x + 5y - 3z = 3 \n" ); document.write( " 4x - y + 7z = 15 \n" ); document.write( "--------------------adding eliminates z \n" ); document.write( "9x + 6y = 23 \n" ); document.write( ": \n" ); document.write( "use the first two original equations, mult the 1st by 3, the 2nd by 4 \n" ); document.write( "-9x - 6y + 12z = -15 \n" ); document.write( " 8x + 20y -12z = 12 \n" ); document.write( "--------------------adding eliminates z \n" ); document.write( "-x + 14y = -3 \n" ); document.write( ": \n" ); document.write( "the above equation by 9, add to the 1st \"two unknown\" equation \n" ); document.write( "-9x + 126y = -27 \n" ); document.write( " 9x + 6y = 23 \n" ); document.write( "------------------adding eliminates x find y \n" ); document.write( " 132y = -4 \n" ); document.write( "y = 4/132 = -1/33, -.0303 as a decimal \n" ); document.write( ": \n" ); document.write( "Find x using 9x + 6y = 23 \n" ); document.write( "9x + 6(-1/33) = 23 \n" ); document.write( "9x + (-6/33) = 23 \n" ); document.write( "9x + (-2/11) = 23 \n" ); document.write( "9x = 23 + 2/11 \n" ); document.write( "9x = 253/11 + 2/11 \n" ); document.write( "9x = 255/11 \n" ); document.write( "x = 1/9 * 251/11 = 255/99, 2.576 as a decimal \n" ); document.write( ": \n" ); document.write( "Find z using 4x - y + 7z = 15, \n" ); document.write( "use decimals, here, avoid these disgusting fractions \n" ); document.write( "4(2.576) - (-.0303) + 7z = 15 \n" ); document.write( "10.303 + .0303 + 7z = 15 \n" ); document.write( "10.333 + 7z = 15 \n" ); document.write( "7z = 15 - 10.333 \n" ); document.write( "7z = 4.667 \n" ); document.write( "z = 4.667/7 \n" ); document.write( "z = .6666, which is 2/3 if you insist on fractions \n" ); document.write( ": \n" ); document.write( "Summarize this mess: x = 2.576, y = -.0303, z = .667 \n" ); document.write( ": \n" ); document.write( "You can confirm this in the original equations, if you are totally bored with life.\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |