document.write( "Question 1158459: given two terms in an arithmetic sequence, find the explicit formula\r
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Algebra.Com's Answer #781405 by ikleyn(52788)\"\" \"About 
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document.write( "There are 30-16 = 14 gaps between the terms \"a%5B30%5D\"  and  \"a%5B16%5D\".\r\n" );
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document.write( "Each gap is  \"%28203-105%29%2F14\" = 7 units long.\r\n" );
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document.write( "So, the 16-th term of the arithmetic progression is  \"a%5B16%5D\" = 105,  and the common difference is  d = 7.\r\n" );
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document.write( "Now you can find the first term from the equation\r\n" );
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document.write( "    \"a%5B16%5D\" = \"a%5B1%5D\" + 7*15,\r\n" );
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document.write( "    105 = \"a%5B1%5D\" + 105\r\n" );
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document.write( "    \"a%5B1%5D\" = 0.\r\n" );
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document.write( "Hence, the formula for the general term is\r\n" );
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document.write( "    \"a%5Bn%5D\" = \"a%5B1%5D\" + d*(n-1) = 0 + 7*(n-1) = 7*(n-1).\r\n" );
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\n" ); document.write( "\n" ); document.write( "For introductory lessons on arithmetic progressions see \r
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\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
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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
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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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