document.write( "Question 1008284: Solve each system by substitution.\r
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Algebra.Com's Answer #624025 by ikleyn(52798) $\"\"$ $\"About$

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document.write( "-5x - 2y =  7   (1)\r\n" );
document.write( " 7x +  y = -8   (2)\r\n" );
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document.write( "Express y from the equation (2): y = -7x - 8, and substitute it into the equation (1).\r\n" );
document.write( "You will get one single equation for x:\r\n" );
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document.write( "-5x - 2(-7x - 8) = 7.\r\n" );
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document.write( "Simplify and solve it:\r\n" );
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document.write( "-5x + 14x + 16 = 7,\r\n" );
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document.write( "9x = 7 - 16 = -9,\r\n" );
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document.write( "x = -1.\r\n" );
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document.write( "Now substitute the found value x = -1 into equation (2) and find y:\r\n" );
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document.write( "-7 + y = -8   ----->   y = -8 + 7 = -1.\r\n" );
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