document.write( "Question 206942: two technicians can complete a mailing in 3 hours when working together. alone, one can complete the mailing 2 hours faster than the other. how long will it take each person to complete the mailing alone? compute answer to two decimal places. \n" ); document.write( "
Algebra.Com's Answer #156439 by nerdybill(7384)\"\" \"About 
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two technicians can complete a mailing in 3 hours when working together. alone, one can complete the mailing 2 hours faster than the other. how long will it take each person to complete the mailing alone? compute answer to two decimal places.
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\n" ); document.write( "Let x = time it takes to complete mailing by slower tech
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\n" ); document.write( "x-2 = time it takes by faster tech
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\n" ); document.write( "3(1/x + 1/(x-2)) = 1
\n" ); document.write( "3/x + 3/(x-2) = 1
\n" ); document.write( "Multiply both sides by a common denominator x(x-2):
\n" ); document.write( "3(x-2) + 3x = x(x-2)
\n" ); document.write( "3x-6 + 3x = x^2-2x
\n" ); document.write( "6x-6 = x^2-2x
\n" ); document.write( "-6 = x^2-8x
\n" ); document.write( "0 = x^2-8x+6
\n" ); document.write( "Solve using the quadratic equation yields:
\n" ); document.write( "x = {7.16, 0.84}
\n" ); document.write( "We can throw out the 0.84 solution because it will give a negative answer for the faster tech leaving us with:
\n" ); document.write( "x = 7.16 hours for the slower tech
\n" ); document.write( "x-2 = 7.16-2 = 5.16 hours for the faster tech
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\n" ); document.write( "Details of quadratic follows:
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"1x%5E2%2B-8x%2B6+=+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=%28-8%29%5E2-4%2A1%2A6=40\".
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\n" ); document.write( " Discriminant d=40 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--8%2B-sqrt%28+40+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%28-8%29%2Bsqrt%28+40+%29%29%2F2%5C1+=+7.16227766016838\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%28-8%29-sqrt%28+40+%29%29%2F2%5C1+=+0.83772233983162\"
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\n" ); document.write( " Quadratic expression \"1x%5E2%2B-8x%2B6\" can be factored:
\n" ); document.write( " \"1x%5E2%2B-8x%2B6+=+1%28x-7.16227766016838%29%2A%28x-0.83772233983162%29\"
\n" ); document.write( " Again, the answer is: 7.16227766016838, 0.83772233983162.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-8%2Ax%2B6+%29\"

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