document.write( "Question 1157839: given two terms in a geometric sequence find the term named in the problem and the explicit formula\r
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Algebra.Com's Answer #780799 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!

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\n" ); document.write( "\n" ); document.write( "a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio \"r\"\r
\n" ); document.write( "\n" ); document.write( "We can also calculate any term using the Rule:\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D=a%5B1%5D%2Ar%5E%28n-1%29\"\r
\n" ); document.write( "\n" ); document.write( "given:\r
\n" ); document.write( "\n" ); document.write( "\"a%5B6%5D=-128\"->\"n=6\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B6%5D=a%5B1%5D%2Ar%5E%286-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"-128=a%5B1%5D%2Ar%5E5\"........solve for \"a%5B1%5D\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=-128%2Fr%5E5\"......eq.1\r
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\n" ); document.write( "\n" ); document.write( "\"a%5B3%5D=-16\"->\"n=3\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B3%5D=a%5B1%5D%2Ar%5E%283-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"-16=a%5B1%5D%2Ar%5E2\"........solve for \"a%5B1%5D\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=-16%2Fr%5E2\"......eq.2\r
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\n" ); document.write( "\n" ); document.write( "from eq.1 and eq.2 we have\r
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\n" ); document.write( "\n" ); document.write( "\"-128%2Fr%5E5=-16%2Fr%5E2\".......cross multiply\r
\n" ); document.write( "\n" ); document.write( "\"-128r%5E2=-16r%5E5\".....both sides divide by \"r%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"-128=-16r%5E3\"\r
\n" ); document.write( "\n" ); document.write( "\"r%5E3=-128%2F-16\"\r
\n" ); document.write( "\n" ); document.write( "\"r%5E3=8\"\r
\n" ); document.write( "\n" ); document.write( "\"r%5E3=2%5E3\"\r
\n" ); document.write( "\n" ); document.write( "\"r=2\"\r
\n" ); document.write( "\n" ); document.write( "go to\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=-16%2Fr%5E2\"......eq.2, substitute \"r\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=-16%2F2%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=-16%2F4\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=-4\"\r
\n" ); document.write( "\n" ); document.write( "nth term formula is:\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D=%28-4%29%2A2%5E%28n-1%29\"\r
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\n" ); document.write( "\n" ); document.write( "find \"a%5B12%5D\"->\"n=12\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B12%5D=%28-4%29%2A2%5E%2812-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B12%5D=%28-4%29%2A2%5E11\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B12%5D=%28-4%29%2A2048\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B12%5D=-8192\"\r
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\n" ); document.write( "\n" ); document.write( "24.\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D=a%5B1%5D%2Ar%5E%28n-1%29\"\r
\n" ); document.write( "\n" ); document.write( "given:\r
\n" ); document.write( "\n" ); document.write( "\"a%5B5%5D=48\"->\"n=5\"\r
\n" ); document.write( "\n" ); document.write( "\"48=a%5B1%5D%2Ar%5E%285-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"48=a%5B1%5D%2Ar%5E4\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=48%2Fr%5E4\".....eq.1
\n" ); document.write( "\"a%5B4%5D=24\"->\"n=4\"\r
\n" ); document.write( "\n" ); document.write( "\"24=a%5B1%5D%2Ar%5E%284-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"24=a%5B1%5D%2Ar%5E3\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=24%2Fr%5E3\".....eq.2\r
\n" ); document.write( "\n" ); document.write( "from eq.1 and eq.2 we have\r
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\n" ); document.write( "\n" ); document.write( "\"48%2Fr%5E4=24%2Fr%5E3\"\r
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\n" ); document.write( "\n" ); document.write( "\"48r%5E3=24r%5E4\"\r
\n" ); document.write( "\n" ); document.write( "\"48=24r\"\r
\n" ); document.write( "\n" ); document.write( "\"r=48%2F24\"\r
\n" ); document.write( "\n" ); document.write( "\"r=2\"\r
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\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=24%2Fr%5E3\".....eq.2, plug in \"r\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=24%2F2%5E3\" \r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=24%2F8\" \r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=3\" \r
\n" ); document.write( "\n" ); document.write( "then,\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D=3%2A2%5E%28n-1%29\"\r
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\n" ); document.write( "\n" ); document.write( "find \"a%5B9%5D\"->\"n=9\" \r
\n" ); document.write( "\n" ); document.write( "\"a%5B9%5D=3%2A2%5E%289-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B9%5D=3%2A2%5E8\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B9%5D=3%2A256\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B9%5D=768\"\r
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