document.write( "Question 72200This question is from textbook algrbra
\n" ); document.write( ": linear systems by addition\r
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\n" ); document.write( "6x+5y=7 \n" ); document.write( "
Algebra.Com's Answer #51606 by rmromero(383)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "In solving systems of linear equation, we can do it by sustitution method\r\n" );
document.write( "Elimination or graphing.\r\n" );
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document.write( "You are told to solve it by addition or Elimination Method.\r\n" );
document.write( "We are to eliminate one variable then solve for the other variable.\r\n" );
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document.write( "say we have 3x - 7y = 13 \r\n" );
document.write( "      and   6x + 5y = 7\r\n" );
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document.write( "Now, you choose which variable to eliminate.Choose x\r\n" );
document.write( "Since we have 3x and 6x by adding them we cant eliminate that variable.\r\n" );
document.write( "So we need to multiply a certain number to do that.\r\n" );
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document.write( "             -2(3x - 7y = 13)  multiply -2 to the first equation\r\n" );
document.write( "               (6x + 5y = 7)\r\n" );
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document.write( "             -6x + 14y = -26  Notice that if -6x + 6x = 0\r\n" );
document.write( "              6x +  5y =  7   x is eliminated y is left.\r\n" );
document.write( "              _____________\r\n" );
document.write( "                 + 19y = -19  Then solve for the other variable y.\r\n" );
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document.write( "                   19y = -19  Divide both sides by -19\r\n" );
document.write( "                     y = -1\r\n" );
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document.write( "Then substitute the value of y which is -1 to any of the 2 equations\r\n" );
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document.write( "     3x - 7y = 13, y = -1\r\n" );
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document.write( "     3x - 7(-1) = 13\r\n" );
document.write( "         3x + 7 = 13\r\n" );
document.write( "     3x + 7 - 7 = 13 - 7       subtract 7 both sides\r\n" );
document.write( "             3x = 6            Divide both sides by 3\r\n" );
document.write( "              x = 2\r\n" );
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document.write( "So the solution is (2, -1)\r\n" );
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document.write( "If you want to check if your answer is right,\r\n" );
document.write( "Substitute x = 2 and y = -1 to both equation.\r\n" );
document.write( "If both equation were true after substituting, then your answer is correct.\r\n" );
document.write( "You try checking ok.\r\n" );
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document.write( "Happy calculating\r\n" );
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document.write( "Rachel\r\n" );
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