document.write( "Question 891275: what is the position to term rule for 9,7,5,3,1,-1,-3 \n" ); document.write( "
Algebra.Com's Answer #539629 by Edwin McCravy(20056)\"\" \"About 
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9,7,5,3,1,-1,-3
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document.write( "Subtract each pair of adjacent terms [right minus left]\r\n" );
document.write( "7-9=-2, 5-7=-2, 3-5=-2, 1-3=-2, -1-1=-2, -3-(-1)=-3+1=-2\r\n" );
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document.write( "9   7   5   3   1  -1  -3\r\n" );
document.write( " \ / \ / \ / \ / \ / \ /\r\n" );
document.write( " -2  -2  -2  -2  -2  -2\r\n" );
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document.write( "So the common difference = -2\r\n" );
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document.write( "So we write \r\n" );
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document.write( "Tn = -2n ± __\r\n" );
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document.write( "Now we need to find out whether to use + or -\r\n" );
document.write( "and what number to place in the blank.\r\n" );
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document.write( "We look at the first term, 9 and ask the question:\r\n" );
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document.write( "What do we need to add to or subtract from -2 to get 9?\r\n" );
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document.write( "Answer: We need to add 11 to -2 to get 9.  \r\n" );
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document.write( "Therefore, we use a plus sign and put 11 in the blank:\r\n" );
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document.write( "So the answer is:\r\n" );
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document.write( "Tn = -2n + 11.\r\n" );
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document.write( "Go to this site:  http://www.youtube.com/watch?v=sx8E1Y3VHms\r\n" );
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document.write( "Edwin

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