document.write( "Question 358617: the sum of two numbers is the same as their product, and the difference of thier reciprocals is 3. find the numbers \n" ); document.write( "
Algebra.Com's Answer #255963 by Edwin McCravy(20056)\"\" \"About 
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the sum of two numbers is the same as their product, and the difference of thier recoprocals is 3. find the numbers
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document.write( "Let the numbers be x and y\r\n" );
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document.write( "The sum of the the numbers = x + y\r\n" );
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document.write( "The product of the numbers = xy\r\n" );
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document.write( "The reciprocal of x is \"1%2Fx\"\r\n" );
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document.write( "The reciprocal of y is \"1%2Fy\"\r\n" );
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document.write( "\"the sum of two numbers x+y is the same as their product xy\",\r\n" );
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document.write( "so  \r\n" );
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document.write( "\"x+%2B+y\"\"%22%22=%22%22\"\"xy\" \r\n" );
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document.write( "\"the difference of their recoprocals \"1%2Fx\"\"%22%22-%22%22\"\"1%2Fy\" is 3\",\r\n" );
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document.write( "so  \r\n" );
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document.write( "\"1%2Fx\"\"%22%22-%22%22\"\"1%2Fy\"\"%22%22=%22%22\"\"3\"\r\n" );
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document.write( "So we have the system of equations \r\n" );
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document.write( "\"system%28x%2By=xy%2C1%2Fx-1%2Fy=3%29\"\r\n" );
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document.write( "Clear the second equation of fractions by multiplying through by LCD xy\r\n" );
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document.write( "\"xy\"\"%22%22%2A%22%22\"\"1%2Fx\"\"%22%22-%22%22\"\"xy\"\"%22%22%2A%22%22\"\"1%2Fy\"\"%22%22=%22%22\"\"xy\"\"%22%22%2A%22%22\"\"3\"\r\n" );
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document.write( "\"cross%28x%29y\"\"%22%22%2A%22%22\"\"1%2Fcross%28x%29\"\"%22%22-%22%22\"\"x%2Across%28y%29\"\"%22%22%2A%22%22\"\"1%2Fcross%28y%29\"\"%22%22=%22%22\"\"3xy\"\r\n" );
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document.write( "\"y-x\"\"%22%22=%22%22\"\"3xy\"\r\n" );
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document.write( "So the system  of equations is now\r\n" );
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document.write( "\"system%28x%2By=xy%2Cy-x=3xy%29\"\r\n" );
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document.write( "Write the left side of the first equation in reverse order:\r\n" );
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document.write( "\"system%28y%2Bx=xy%2Cy-x=3xy%29\"\r\n" );
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document.write( "Adding the two equations term by term,\r\n" );
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document.write( "2y = 4xy\r\n" );
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document.write( "Get 0 on the right side:\r\n" );
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document.write( "2y - 4xy = 0\r\n" );
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document.write( "Divide through by 2\r\n" );
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document.write( "y - 2xy = 0\r\n" );
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document.write( "y(1 - 2x) = 0\r\n" );
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document.write( "Set each factor = 0\r\n" );
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document.write( "y = 0;   1 - 2x = 0\r\n" );
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document.write( "            -2x = -1\r\n" );
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document.write( "              x = \"1%2F2\"\r\n" );
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document.write( "y = 0 must be discarded because the reciprocal of 0 is not defined.\r\n" );
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document.write( "So x = \"1%2F2\"  \r\n" );
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document.write( "Substituting in \r\n" );
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document.write( "\"x%2By\"\"%22%22=%22%22\"\"xy\"\r\n" );
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document.write( "\"1%2F2%2By\"\"%22%22=%22%22\"\"expr%281%2F2%29y\"\r\n" );
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document.write( "Multiplying through by LCD of 2\r\n" );
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document.write( "1 + 2y = y\r\n" );
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document.write( "     y = -1\r\n" );
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document.write( "So the numbers are \"1%2F2\" and \"-1\"\r\n" );
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document.write( "Checking:\r\n" );
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document.write( "The sum of the the numbers = \"1%2F2%2B%28-1%29=1%2F2-1=1%2F2-2%2F2=-1%2F2\"\r\n" );
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document.write( "The product of the numbers = \"expr%281%2F2%29%28-1%29+=-1%2F2\"\r\n" );
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document.write( "That checks because they are both the same.\r\n" );
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document.write( "The reciprocal of \"1%2F2\" is 2\r\n" );
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document.write( "The reciprocal of -1 is \"1%2F%28-1%29\" or -1.\r\n" );
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document.write( "The difference of these reciprocals is \"2-%28-1%29=2%2B1=3\"\r\n" );
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document.write( "So that checks.\r\n" );
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document.write( "Edwin
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