document.write( "Question 170362: Find X, Y, and Z.
\n" ); document.write( "5x + 4y - 2z = 3
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\n" ); document.write( "2x + 5y + 4z = -5 \n" ); document.write( "

Algebra.Com's Answer #125761 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "Find x, y, and z.\r\n" );
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document.write( "Pick any letter and a pair of equations to eliminate that letter\r\n" );
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document.write( "I pick the letter y, and the 1st and 2nd equations to eliminate\r\n" );
document.write( "y from.\r\n" );
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document.write( "To eliminate y, we multiply the second equation through by 2\r\n" );
document.write( "and add them term by term:\r\n" );
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document.write( "Now pick a DIFFERENT pair of equations and eliminate\r\n" );
document.write( "the SAME letter, y, from them. I'll pick the 2nd and\r\n" );
document.write( "3rd equations.  (You have to choose one of them the\r\n" );
document.write( "same as before, but be sure to pick the other one as\r\n" );
document.write( "the equation you have not yet used:\r\n" );
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document.write( "To eliminate y, we multiply the upper equation through\r\n" );
document.write( "by 5 and the lower equation through by 2, and add them \r\n" );
document.write( "term by term:\r\n" );
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document.write( "Notice that this equation can be divided through by 3.\r\n" );
document.write( "It isn't necessary to do this but if we do the numbers\r\n" );
document.write( "will be smaller.  So I will divide it through by 3:\r\n" );
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document.write( "Now we take these two equations and now we have two\r\n" );
document.write( "equations with two unknowns:\r\n" );
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document.write( "To eliminate z, multiply the first equation by -11,\r\n" );
document.write( "and the second equation through by +8:\r\n" );
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document.write( "Add them term by term:\r\n" );
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document.write( "Substitute that into\r\n" );
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document.write( "Now go back and pick any of the\r\n" );
document.write( "original equations which contains\r\n" );
document.write( "y, and substitute these value for\r\n" );
document.write( "x and z:\r\n" );
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document.write( "Picking the first original equation:\r\n" );
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document.write( "Solution:\r\n" );
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document.write( "Edwin

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