document.write( "Question 1094949: Determine the value of t1 for an arithmetic sequence, where d = –4 and S14 = 1 120
\n" ); document.write( "Ive been having so much trouble trying to figure out how to find t1 without Tn or n.
\n" ); document.write( "(d= change in each term
\n" ); document.write( "S14=sum of the 14th term) \n" ); document.write( "
Algebra.Com's Answer #709520 by ikleyn(52794)\"\" \"About 
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document.write( "The formula for the sum of the first n terms of an AP is\r\n" );
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document.write( "\"S%5Bn%5D\" = \"%28a%5B1%5D%2B+%28%28n-1%29%2Ad%29%2F2%29%2An\".\r\n" );
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document.write( "At n = 14\r\n" );
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document.write( "\"S%5B14%5D\" = \"%28a%5B1%5D%2B+%28%2814-1%29%2A%28-4%29%29%2F2%29%2A14\",   or\r\n" );
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document.write( "1120 = \"%28a%5B1%5D+-+13%2A2%29%2A14\",\r\n" );
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document.write( "which implies  \"a%5B1%5D+-+26\" = \"1120%2F14\" = 80  ====>  \"a%5B1%5D\" = 80 + 26 = 106.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On arithmetic progressions, see the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - The proofs of the formulas for arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Problems on arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Word problems on arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Mathematical induction and arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - One characteristic property of arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - Solved problems on arithmetic progressions \r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \"Arithmetic progressions\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-II
\n" ); document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "into your archive and use when it is needed.\r
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