document.write( "Question 1015160: (x+2k)^2 + (y-3k)^2 = 25 pass through the point (1,0)
\n" ); document.write( "find value of k
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Algebra.Com's Answer #631514 by Alan3354(69443)\"\" \"About 
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(x+2k)^2 + (y-3k)^2 = 25 pass through the point (1,0)
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\n" ); document.write( "(-2k,3k) is the center of the given circle, call it C.
\n" ); document.write( "The distance from (-2k,3k) to (1,0) = 5
\n" ); document.write( "--> 25 = (-2k-1)^2 + (3k)^2 = 4k^2 + 4k + 1 + 9k^2
\n" ); document.write( "13k^2 + 4k - 24 = 0
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Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"13x%5E2%2B4x%2B-24+=+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%2A13%2A-24=1264\".
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\n" ); document.write( " Discriminant d=1264 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28-4%2B-sqrt%28+1264+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%284%29%2Bsqrt%28+1264+%29%29%2F2%5C13+=+1.21356837189471\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%284%29-sqrt%28+1264+%29%29%2F2%5C13+=+-1.52126067958701\"
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\n" ); document.write( " Quadratic expression \"13x%5E2%2B4x%2B-24\" can be factored:
\n" ); document.write( " \"13x%5E2%2B4x%2B-24+=+%28x-1.21356837189471%29%2A%28x--1.52126067958701%29\"
\n" ); document.write( " Again, the answer is: 1.21356837189471, -1.52126067958701.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+13%2Ax%5E2%2B4%2Ax%2B-24+%29\"

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\n" ); document.write( "k = the 2 values above.
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\n" ); document.write( "There are 2 circles of r = 5 that fit.
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