document.write( "Question 55652: The sum of the reciprocals of two consecutive odd integers is 8/15. Find the integers. Thank you. \n" ); document.write( "
Algebra.Com's Answer #37760 by aaaaaaaa(138)\"\" \"About 
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reciprocal of x = the number which multiplied by x gives 1.\r
\n" ); document.write( "\n" ); document.write( "Therefore, we can express the reciprocal of x as \"1%2Fx\".\r
\n" ); document.write( "\n" ); document.write( "So now, let's assign the variables to the values:\r
\n" ); document.write( "\n" ); document.write( "First number = 2x+1
\n" ); document.write( "Second number = 2x+3
\n" ); document.write( "Reciprocal of first = \"1%2F%282x%2B1%29\"
\n" ); document.write( "Reciprocal of second = \"1%2F%282x%2B3%29\"\r
\n" ); document.write( "\n" ); document.write( "The assugnment of the two numbers requires ome explanation. As the problem requires the two numbers to be odd, we use a little trick (that 2x is always even), to determine that 2x+1 and 2x+3 will be always odd.\r
\n" ); document.write( "\n" ); document.write( "\"1%2F%282x%2B1%29+%2B+1%2F%282x%2B3%29+=+8%2F15\"
\n" ); document.write( "Take the lcm of the denominators (it's \"15%282x%2B1%29%282x%2B3%29\"):
\n" ); document.write( "\"15%282x%2B3%29+%2B+15%282x%2B1%29+=+8%282x%2B3%29%282x%2B1%29\"
\n" ); document.write( "\"30x+%2B+45+%2B+30x+%2B+15+=+32x%5E2+%2B+64x+%2B+24\"
\n" ); document.write( "\"60x+%2B+60+=+32x%5E2+%2B+64x+%2B+24\"
\n" ); document.write( "\"32x%5E2+%2B+4x+-+36+=+0\"
\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"32x%5E2%2B4x%2B-36+=+0\") has the following solutons:
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\n" ); document.write( " \"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%284%29%5E2-4%2A32%2A-36=4624\".
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\n" ); document.write( " Discriminant d=4624 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28-4%2B-sqrt%28+4624+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%284%29%2Bsqrt%28+4624+%29%29%2F2%5C32+=+1\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%284%29-sqrt%28+4624+%29%29%2F2%5C32+=+-1.125\"
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\n" ); document.write( " Quadratic expression \"32x%5E2%2B4x%2B-36\" can be factored:
\n" ); document.write( " \"32x%5E2%2B4x%2B-36+=+32%28x-1%29%2A%28x--1.125%29\"
\n" ); document.write( " Again, the answer is: 1, -1.125.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+32%2Ax%5E2%2B4%2Ax%2B-36+%29\"

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\n" ); document.write( "\n" ); document.write( "Since 1.125 is not an integer, x = 1, first = 3 and second = 5.
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