document.write( "Question 992588: Find all points on the y-axis that are a distance 7 from P(5, 9). \n" ); document.write( "
Algebra.Com's Answer #612181 by macston(5194)\"\" \"About 
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\n" ); document.write( "Point(\"x%5B2%5D\",\"y%5B2%5D\")=(\"5\",\"9\")
\n" ); document.write( "Point(\"x%5B1%5D\".\"y%5B1%5D\")=(\"0\",\"y\")
\n" ); document.write( "d=distance=7
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\n" ); document.write( "\"d=sqrt%28%28x%5B2%5D-x%5B1%5D%29%5E2%2B%28y%5B2%5D-y%5B1%5D%29%5E2%29\"
\n" ); document.write( "\"7=sqrt%28%285-0%29%5E2%2B%289-y%29%5E2%29\"
\n" ); document.write( "\"7=sqrt%285%5E2%2B%289-y%29%5E2%29\"
\n" ); document.write( "\"49=25%2B%289-y%29%5E2\"
\n" ); document.write( "\"24=y%5E2-18y%2B81\"
\n" ); document.write( "\"0=y%5E2-18y%2B57\"
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ay%5E2%2Bby%2Bc=0\" (in our case \"1y%5E2%2B-18y%2B57+=+0\") has the following solutons:
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\n" ); document.write( " \"y%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=%28-18%29%5E2-4%2A1%2A57=96\".
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\n" ); document.write( " Discriminant d=96 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--18%2B-sqrt%28+96+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"y%5B1%5D+=+%28-%28-18%29%2Bsqrt%28+96+%29%29%2F2%5C1+=+13.8989794855664\"
\n" ); document.write( " \"y%5B2%5D+=+%28-%28-18%29-sqrt%28+96+%29%29%2F2%5C1+=+4.10102051443364\"
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\n" ); document.write( " Quadratic expression \"1y%5E2%2B-18y%2B57\" can be factored:
\n" ); document.write( " \"1y%5E2%2B-18y%2B57+=+1%28y-13.8989794855664%29%2A%28y-4.10102051443364%29\"
\n" ); document.write( " Again, the answer is: 13.8989794855664, 4.10102051443364.\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-18%2Ax%2B57+%29\"

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\n" ); document.write( "y=4.1 or 13.9
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\n" ); document.write( "ANSWER: There are two points: (0,4.1) and (0,13.9)
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