document.write( "Question 27858: 4x+2y=14
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document.write( "7x-3y=-8 \n" );
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Algebra.Com's Answer #15172 by Sridi(6)![]() ![]() ![]() You can put this solution on YOUR website! We need to eliminate one of the variables first to solve the system of equations. \n" ); document.write( "either we can eliminate the x variable, solve for y first or the other way around.\r \n" ); document.write( "\n" ); document.write( "Let us call \n" ); document.write( "4x+2y=14 --------Equation 1 \n" ); document.write( "7x-3y=-8 -------- Equation 2\r \n" ); document.write( "\n" ); document.write( "Now multiply the entire equation 1 by 3 and equation 2 by 2\r \n" ); document.write( "\n" ); document.write( "(4x+2y=14) * 3 \n" ); document.write( "(7x-3y=-8) * 2\r \n" ); document.write( "\n" ); document.write( "we will get\r \n" ); document.write( "\n" ); document.write( "12x + 6y = 42 -------Equation 1a \n" ); document.write( "14x -6y = - 16 ------- Equation 2b\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now add equation 1a and 2b\r \n" ); document.write( "\n" ); document.write( "The =6y will cancel with -6y\r \n" ); document.write( "\n" ); document.write( "You are left with \n" ); document.write( "26x = 26\r \n" ); document.write( "\n" ); document.write( "X = 26/26\r \n" ); document.write( "\n" ); document.write( "X = 1\r \n" ); document.write( "\n" ); document.write( "Now substitute x = 1 in equation 1\r \n" ); document.write( "\n" ); document.write( "4(1) + 2y = 14\r \n" ); document.write( "\n" ); document.write( "2y+4 + 14\r \n" ); document.write( "\n" ); document.write( "2y = 14- 4 = 10\r \n" ); document.write( "\n" ); document.write( "2y = 10\r \n" ); document.write( "\n" ); document.write( "y = 5\r \n" ); document.write( "\n" ); document.write( "Now check with equation 2 with x = 1 and y = 5\r \n" ); document.write( "\n" ); document.write( "7(1) - 3(5) = 7 - 15 = -8.\r \n" ); document.write( "\n" ); document.write( "We have proved that 7x - 3y = -8 just like equation 2 is with the values we calculated for x and y. hence x =1, and y = 5 are correct answers for the sytem of equation given.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |