document.write( "Question 1131474: Given an arithmetic progression 2, -1,-4,.., state three consecutive terms in this progression which sum up to -84. \n" ); document.write( "

Algebra.Com's Answer #748167 by ikleyn(52803) $\"\"$ $\"About$

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document.write( "Without any long computations, you must know that the middle term of the tree terms of an arithmetic progression, \r\n" );
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document.write( "that sum up to -84,  is one third of -84, i.e.   = -28.\r\n" );
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document.write( "Since the common difference of the progression is -3, the terms are\r\n" );
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document.write( "    -25, -28, -31.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Why it is so ?\r
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\n" ); document.write( "\n" ); document.write( "Because if (m-d), m and (m+d) are three consecutive terms of any AP, that sum up to S, then\r
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document.write( "    (m-d) + m + (m+d) = S   ====>   3m = S   ====>   m = .\r\n" );
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\n" ); document.write( "\n" ); document.write( "For introductory lessons on arithmetic progressions see \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( "in this site.\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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