document.write( "Question 160537:
\n" ); document.write( "I need to solve this using any method. Id like to see the steps and the correct
\n" ); document.write( "answer. I think maybe I should start by multiplying the 3rd equation by 2 and
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Algebra.Com's Answer #118386 by Edwin McCravy(20077) $\"\"$ $\"About$

You can put this solution on YOUR website!
Edwin's solution:
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document.write( "That would work, but it would be the best way.\r\n" );
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document.write( "First you should observe that z is already eliminated\r\n" );
document.write( "from the third equation, so you should eliminate z \r\n" );
document.write( "from the first two equations:\r\n" );
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document.write( "To eliminate z from the first two equations:\r\n" );
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document.write( "Multiply the first equation by 3 and the second equation \r\n" );
document.write( "by 7, then add them:\r\n" );
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document.write( "3[-10x - 11y + 7z = 145]\r\n" );
document.write( "7[  7x -  4y - 3z =  53]\r\n" );
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document.write( "  -30x - 33y + 21z = 435\r\n" );
document.write( "   49x - 28y - 21z = 371\r\n" );
document.write( "   19x - 61y       = 806\r\n" );
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document.write( "Now we take the third original equation with\r\n" );
document.write( "this equation and solve this system:\r\n" );
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document.write( "We can do this by substitution:\r\n" );
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document.write( "Solve the first equation for y:\r\n" );
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document.write( "Substitute  for  in\r\n" );
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document.write( "Substitute that into \r\n" );
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document.write( "Now substitute  and  into\r\n" );
document.write( "either one of the first two original equations.\r\n" );
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document.write( "Edwin

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