document.write( "Question 1026097: Write the sum using summation notation, assuming the suggested pattern continues.\r
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Algebra.Com's Answer #641362 by ikleyn(52788) $\"\"$ $\"About$

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\n" ); document.write( "Write the sum using summation notation, assuming the suggested pattern continues.\r
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document.write( "-4 + 5 + 14 + 23 + ... + 131 = .\r\n" );
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document.write( "This is the sum of the first 16 terms of an arithmetic progression with the first term -4 and the common difference 9.\r\n" );
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document.write( "The last term is 16-th (at k = 16), and it is equal to -4 + (16-1)*9 = -4 + 15*9 = 131.\r\n" );
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document.write( "On arithmetic progressions see the lesson Arithmetic progressions in this site, and the lessons associated with it.\r\n" );
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\n" ); document.write( "\n" ); document.write( "comment from student: Thanks! I have one last question: Write the sum using summation notation, assuming
\n" ); document.write( "the suggested pattern continues. -9 - 3 + 3 + 9 + ... + 81. \r
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document.write( "-9 - 3 + 3 + 9 + ... + 81 = .\r\n" );
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document.write( "This is the sum of the first 16 terms of an arithmetic progression with the first term -9 and the common difference 6.\r\n" );
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document.write( "The last term is 16-th (at k = 16), and it is equal to -9 + (16-1)*6 = -9 + 15*6 = 81.\r\n" );
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