document.write( "Question 999141: solve using addition method\r
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document.write( "3x+7y=16
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document.write( "2x-3y=-11 \n" );
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Algebra.Com's Answer #616849 by Theo(13342)![]() ![]() You can put this solution on YOUR website! your equations are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3x+7y=16 \n" ); document.write( "2x-3y=-11\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "multiply both sides of the first equation by 2 and multiply both sides of the second equation by 3 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "6x + 14y = 32 \n" ); document.write( "6x - 9y = -33\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "subtract the second equation from the first to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "23y = 65\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solve for y to get y = 65/23\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "replace y with 65/23 in the original first equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3x+7y=16 becomes: \n" ); document.write( "3x + 7*65/23 = 16\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3x + 455/23 = 16\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "multiply both sides of this equation by 23 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "69x + 455 = 368\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "subtract 455 from both sides of this equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "69x = 368 - 455\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "69x = -87\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide both sides of this equation by 69 to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = -87/69\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you have:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = -87/69 \n" ); document.write( "y = 65/23\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "to confirm these solutions are correct, replace x and y in the original equations to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3x+7y=16 \n" ); document.write( "2x-3y=-11\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "become:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3*-87/69 + 7*65/23 = 16 \n" ); document.write( "2*-87/69 - 3*65/23 = -11\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "evaluate both equations using your calculator (unless you want to punish yourself by doing the math manually) to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "16 = 16 \n" ); document.write( "-11 = -11\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the solutions are confirmed as good.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = -87/69 \n" ); document.write( "y = 65/23\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = -87/69 can be simplified to x = -29/23 \n" ); document.write( "y = 65/23 remains at y = 65/23 since it cannot be simplified any further.\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |