document.write( "Question 748403: how do i solve the following matrix by hand? \r
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Algebra.Com's Answer #455479 by AnlytcPhil(1807)\"\" \"About 
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document.write( "eq. 1   2x+ y    =  -4\r\n" );
document.write( "eq. 2     -2y+4z =   0\r\n" );
document.write( "eq. 3   3x   -2z = -11\r\n" );
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document.write( "The first equation has no z-term.\r\n" );
document.write( "So eliminate z from the other two terms.\r\n" );
document.write( "Multiply eq. 3 by 2 and add term by term:\r\n" );
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document.write( "          -2y+4z =   0\r\n" );
document.write( "        6x   -4z = -22\r\n" );
document.write( "        --------------\r\n" );
document.write( "        6x-2y    = -22\r\n" );
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document.write( "Divide that through by 2\r\n" );
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document.write( "eq. 4   3x- y    = -11\r\n" );
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document.write( "Now we have a system of two equations and two\r\n" );
document.write( "unknowns:\r\n" );
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document.write( "eq. 1   2x+y =  -4\r\n" );
document.write( "eq. 4   3x-y = -11\r\n" );
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document.write( "We add them term by term and y will be eliminated:\r\n" );
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document.write( "eq. 1   2x+y =  -4\r\n" );
document.write( "eq. 4   3x-y = -11\r\n" );
document.write( "------------------\r\n" );
document.write( "        5x   = -15\r\n" );
document.write( "           x = -3\r\n" );
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document.write( "Substitute x = -3 in eq. 4,\r\n" );
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document.write( "eq. 4   3x-y = -11\r\n" );
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document.write( "     3(-3)-y = -11\r\n" );
document.write( "        -9-y = -11\r\n" );
document.write( "          -y = -2\r\n" );
document.write( "           y = 2\r\n" );
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document.write( "Substitute x = -3 in eq. 3 \r\n" );
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document.write( "eq. 3   3x-2z = -11\r\n" );
document.write( "     3(-3)-2z = -11\r\n" );
document.write( "        -9-2z = -11\r\n" );
document.write( "          -2z = -2\r\n" );
document.write( "            z = 1\r\n" );
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document.write( "Solution (x,y,z) = (-3,2,1)\r\n" );
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document.write( "Edwin
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