document.write( "Question 132604: Two numbers differ by 6 and their reciprocals differ by 8/15.Find the numbers \n" ); document.write( "
Algebra.Com's Answer #96944 by solver91311(24713)\"\" \"About 
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First number: \"x\"
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\n" ); document.write( "\n" ); document.write( "The two numbers differ by 6: \"x-y=6\" We'll just assume that \"x%3Ey\"\r
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\n" ); document.write( "\n" ); document.write( "The reciprocal of the first number: \"1%2Fx\", \"x%3C%3E0\" and because of \"x-y=6\", \"y%3C%3E-6\"
\n" ); document.write( "The reciprocal of the second number: \"1%2Fy\", \"y%3C%3E0\" and because of \"x-y=6\", \"x%3C%3E6\"\r
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\n" ); document.write( "\n" ); document.write( "Their reciprocals differ by 8/15: Since we have assumed that \"x%3Ey\", \"1%2Fx%3C1%2Fy\", so \"1%2Fy-1%2Fx=8%2F15\"\r
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\n" ); document.write( "\n" ); document.write( "Re-write the first equation to solve it for x:
\n" ); document.write( "\"x=y%2B6\"\r
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\n" ); document.write( "\n" ); document.write( "Substitute this expression for x into the second equation in place of x.
\n" ); document.write( "\"1%2Fy-1%2F%28y%2B6%29=8%2F15\"\r
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\n" ); document.write( "\n" ); document.write( "Multiply both sides by 15:
\n" ); document.write( "\"15%2Fy-15%2F%28y%2B6%29=8\"\r
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\n" ); document.write( "\n" ); document.write( "Lowest common denominator is just the product of the two denominators since there are no common factors. So:\r
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\n" ); document.write( "\n" ); document.write( "\"%2815%28y%2B6%29-15y%29%2F%28y%28y%2B6%29%29=%288y%28y%2B6%29%29%2F%28y%28y%2B6%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "Distribute and collect like terms all on the left:
\n" ); document.write( "\"%28-8y%5E2-48y%2B15y%2B90-15y%29%2F%28y%28y%2B6%29%29\"
\n" ); document.write( "\"%28-8y%5E2-48y%2B90%29%2F%28y%28y%2B6%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "Solve the numerator expression for 0, remembering to exclude 0 and -6 as values not in the domain of the function in terms of y.\r
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\n" ); document.write( "\n" ); document.write( "\"-8y%5E2-48y%2B90=0\"\r
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\n" ); document.write( "\n" ); document.write( "Divide by -2:
\n" ); document.write( "\"4y%5E2%2B24y-45=0\"\r
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\n" ); document.write( "\n" ); document.write( "Factor:
\n" ); document.write( "\"%282x-3%29%282x%2B15%29=0\", so y = 1.5 or y = -7.5\r
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\n" ); document.write( "\n" ); document.write( "y = 1.5 => x = 7.5 because \"7.5-1.5=6\", so:\r
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\n" ); document.write( "\n" ); document.write( "\"1%2F1.5-1%2F7.5=5%2F7.5-1%2F7.5=4%2F7.5=8%2F15\" and the first root checks.\r
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\n" ); document.write( "\n" ); document.write( "y = -7.5 => x = -1.5 because \"-1.5-%28-7.5%29=6\", so:\r
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\n" ); document.write( "\n" ); document.write( "\"1%2F%28-7.5%29-1%2F%28-1.5%29=-1%2F7.5%2B5%2F7.5=4%2F7.5=8%2F15\" and the second root checks.
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