document.write( "Question 1051701: Systems of equations in three variables. Solve each system of equations.
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Algebra.Com's Answer #667157 by ikleyn(52788) $\"\"$ $\"About$

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document.write( "2x - y + 2z = 15   (1)\r\n" );
document.write( "-x + y +  z =  3   (2)\r\n" );
document.write( "3x - y + 2z = 18   (3)\r\n" );
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document.write( "Distract equation (1) from equation (2) (both sides). You will get\r\n" );
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document.write( "x = 18 - 15  --->  x = 3. So, you just solved for x.\r\n" );
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document.write( "Next substitute x=3 into (1) and (2). You will get\r\n" );
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document.write( "2*3 - y + 2z = 15    (4)   ( instead of (1) )\r\n" );
document.write( "-3  + y +  z =  3    (5)   ( instead of (2) )\r\n" );
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document.write( "Simplify (4) and (5). You will get\r\n" );
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document.write( "-y + 2z = 15 - 6,\r\n" );
document.write( " y +  z =  3 + 3.\r\n" );
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document.write( "Simplify \r\n" );
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document.write( "-y + 2z = 9,        (6)\r\n" );
document.write( " y +  z = 6.        (7)\r\n" );
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document.write( "Add equations (6) and (7) (both sides). You will get\r\n" );
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document.write( "3z = 9 + 6  --->  3z = 15  --->  z =  = 5.  So, you just solved for z.\r\n" );
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document.write( "Now find y from (7). Please do it on your own.\r\n" );
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