document.write( "Question 928231: find equation of hyperbola where foci is (9,0) and hyperbola passes through (12,3) \n" ); document.write( "
Algebra.Com's Answer #563539 by MathLover1(20850)\"\" \"About 
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find equation of hyperbola where foci is (\"9\",\"0\") and hyperbola passes through (\"12\",\"3\")\r
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\n" ); document.write( "\n" ); document.write( "The general formula of a hyperbola is:\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2+%2F+a%5E2+-+y%5E2+%2F+b%5E2=+1\"\r
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\n" ); document.write( "\n" ); document.write( "Since, (\"12\", \"3\") is a point on the hyperbola, we have:\r
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\n" ); document.write( "\n" ); document.write( "\"12%5E2+%2F+a%5E2+-+3%5E2+%2F+b%5E2+=+1\"\r
\n" ); document.write( "\n" ); document.write( "\"144+%2F+a%5E2+-+9+%2F+b%5E2+=+1\"........eq.(1)\r
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\n" ); document.write( "\n" ); document.write( "Since the foci is (\"9\",\"0\"), we have:\r
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\n" ); document.write( "\n" ); document.write( "\"a%5E2+%2B+b%5E2+=+9%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"b%5E2+=+81+-+a%5E2\".....eq.(2)\r
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\n" ); document.write( "\n" ); document.write( "Substituting (2) into (1), we have:\r
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\n" ); document.write( "\n" ); document.write( "\"144+%2F+a%5E2+-+9+%2F+%2881-a%5E2%29+=+1\" ....common denominator is \"a%5E2%2881-a%5E2%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28144%2881-a%5E2%29-9a%5E2%29%2F%28a%5E2%2881-a%5E2%29%29=1\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28144%2881-a%5E2%29-9a%5E2%29=1%28a%5E2%2881-a%5E2%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"11664-144a%5E2-9a%5E2=81a%5E2-a%5E4\"\r
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\n" ); document.write( "\n" ); document.write( "\"0=144a%5E2%2B81a%5E2%2B9a%5E2-a%5E4-11664\"\r
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\n" ); document.write( "\n" ); document.write( "\"0=234a%5E2-a%5E4-11664\"\r
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\n" ); document.write( "\n" ); document.write( "\"a%5E4-234a%5E2%2B11664=0\"....write \"-234a%5E2\" as \"-162a%5E2-72x%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"a%5E4-162a%5E2-72x%5E2%2B11664=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28a%5E4-162a%5E2%29-%2872x%5E2%2B11664%29=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"a%5E2%28a%5E2-162%29-72%28x%5E2%2B162%29=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28a%5E2-162%29%28a%5E2-72%29+=+0\"\r
\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "=>\"%28a%5E2-162%29+=+0\"=>\"a%5E2+=+162\"\r
\n" ); document.write( "\n" ); document.write( "=>\"%28a%5E2-72%29+=+0\"=>\"a%5E2+=+72\"\r
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\n" ); document.write( "\n" ); document.write( "Suppose \"a%5E2+=+162\", from (2), we have:\r
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\n" ); document.write( "\n" ); document.write( "\"b%5E2+=+81+-+162+=+-81\"=>rejected, since a square cannot be negative \r
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\n" ); document.write( "\n" ); document.write( "Suppose \"a%5E2+=+72\", from (2), we have:\r
\n" ); document.write( "\n" ); document.write( "\"b%5E2+=+81-72+=+9\"=> this solution is accepted\r
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\n" ); document.write( "\n" ); document.write( "Thus, we have:\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2F72+-y%5E2%2F9+=+1\"\r
\n" ); document.write( "\n" ); document.write( "foci is (\"9\",\"0\") and (\"-9\",\"0\")\r
\n" ); document.write( "\n" ); document.write( "hyperbola passes through (\"12\",\"3\")\r
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