document.write( "Question 447917: Plsss solve the System... thanx..... \r
\n" ); document.write( "\n" ); document.write( "x + y + z - 2w = -4
\n" ); document.write( " 2y + z + 3w = 4
\n" ); document.write( "2x+ y - z + 2w = 5
\n" ); document.write( "x - y + w = 4 \n" ); document.write( "
Algebra.Com's Answer #308365 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( " x +  y + z - 2w = -4\r\n" );
document.write( "     2y + z + 3w =  4\r\n" );
document.write( "2x +  y - z + 2w =  5\r\n" );
document.write( " x -  y     +  w =  4\r\n" );
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document.write( "z is already eliminated in the 4th equation,\r\n" );
document.write( "Add the 1st and 3rd equation to eliminate z\r\n" );
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document.write( " x +  y + z - 2w = -4\r\n" );
document.write( "2x +  y - z + 2w =  5\r\n" );
document.write( "---------------------\r\n" );
document.write( "3x + 2y          =  1\r\n" );
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document.write( "Add the 2nd and 3rd equation to eliminate z\r\n" );
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document.write( "     2y + z + 3w =  4\r\n" );
document.write( "2x +  y - z + 2w =  5\r\n" );
document.write( "---------------------\r\n" );
document.write( "2x + 3y     + 5w =  9\r\n" );
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document.write( "So now we have this system of equations\r\n" );
document.write( "in only x, y, and w.  Not z:\r\n" );
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document.write( " x -  y +  w =  4\r\n" );
document.write( "3x + 2y      =  1\r\n" );
document.write( "2x + 3y + 5w =  9\r\n" );
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document.write( "w is already eliminated from the 2nd\r\n" );
document.write( "equation, so multiply the 1st equation\r\n" );
document.write( "by -5 and add it to the 3rd equation:\r\n" );
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document.write( "-5x + 5y - 5w = -20\r\n" );
document.write( " 2x + 3y + 5w =   9\r\n" );
document.write( "-------------------\r\n" );
document.write( "-3x + 8y      = -11\r\n" );
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document.write( "So now we have this system of equations\r\n" );
document.write( "in only x and y.  Not z or w:\r\n" );
document.write( "  \r\n" );
document.write( " 3x + 2y =   1\r\n" );
document.write( "-3x + 8y = -11\r\n" );
document.write( "----------------\r\n" );
document.write( "     10y = -10\r\n" );
document.write( "       y =  -1\r\n" );
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document.write( "Substitute  y = -1 in\r\n" );
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document.write( "    3x + 2y = 1\r\n" );
document.write( " 3x + 2(-1) = 1\r\n" );
document.write( "     3x - 2 = 1\r\n" );
document.write( "         3x = 3\r\n" );
document.write( "          x = 1\r\n" );
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document.write( "Substitute x = 1 and y = -1 in\r\n" );
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document.write( "   x - y + w = 4\r\n" );
document.write( "1 - (-1) + w = 4\r\n" );
document.write( "   1 + 1 + w = 4\r\n" );
document.write( "       2 + w = 4\r\n" );
document.write( "           w = 2\r\n" );
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document.write( "Substitute x = 1, y = -1, and w = 2 in\r\n" );
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document.write( "      x + y + z - 2w = -4\r\n" );
document.write( " 1 + (-1) + z - 2(2) = -4  \r\n" );
document.write( "       1 - 1 + z - 4 = -4\r\n" );
document.write( "               z - 4 = -4\r\n" );
document.write( "                   z = 0\r\n" );
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document.write( "(x,y,z,w) = (1,-1,0,2)\r\n" );
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document.write( "Edwin
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