document.write( "Question 1170498: -2x - 2y = 16 and y = -8
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Algebra.Com's Answer #795366 by Edwin McCravy(20056) $\"\"$ $\"About$

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-2x - 2y = 16 and y = -8
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document.write( "This is the system of two equations in two unknowns x and y:\r\n" );
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document.write( "Start writing the first equation down,\r\n" );
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document.write( "-2x - 2y = 16\r\n" );
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document.write( "except when you come to \"y\", don't write \"y\"; instead write what\r\n" );
document.write( "\"y\" equals from the second equation, putting it in parentheses, \r\n" );
document.write( "which is \"(-)\".  So you write this:\r\n" );
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document.write( "-2x - 2(-8) = 16\r\n" );
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document.write( "Now we replace 2(-8) by the number (-16)\r\n" );
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document.write( "-2x - (-16) = 16\r\n" );
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document.write( "Now we use the definition of subtraction which\r\n" );
document.write( "tells us that subtracting a negative number isd\r\n" );
document.write( "adding the opposite positive number: \r\n" );
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document.write( "Next we add -16 to both sides:\r\n" );
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document.write( "-2x + 16 = 16\r\n" );
document.write( "    - 16  -16\r\n" );
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document.write( "-2x      = 0\r\n" );
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document.write( "Now we want to have just x on the left,\r\n" );
document.write( "so we divide both sides by the coefficient\r\n" );
document.write( "of x, which is -2\r\n" );
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document.write( "Then we cancel the -2's on the left \r\n" );
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document.write( "which leaves\r\n" );
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document.write( "and do the division of 0 by -2 on the right, getting 0\r\n" );
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document.write( "So 0 is the solution for x.\r\n" );
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document.write( "The solution for the system of equations is (x,y) = (0,-8)\r\n" );
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document.write( "Edwin

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