document.write( "Question 1018377: How many terms in the series 19+16+13+... Must be added to a sum of 44? \n" ); document.write( "

Algebra.Com's Answer #634529 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "S_n = [2a₁ + (n-1)d]\r\n" );
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document.write( "44 = [2(19) + (n-1)(-3)]\r\n" );
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document.write( "44 = [38 -3n + 3]\r\n" );
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document.write( "44 = [41 - 3n]\r\n" );
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document.write( "88 = n[41 - 3n]\r\n" );
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document.write( "88 = 41n - 3n²\r\n" );
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document.write( "3n² - 41n + 88 = 0\r\n" );
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document.write( "(3n-8)(n-11) = 0\r\n" );
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document.write( "3n-8 = 0;  n-11 = 0\r\n" );
document.write( "  3n = 8;     n = 11\r\n" );
document.write( "   n = 8/3\r\n" );
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document.write( "The answer n has to be a positive integer,\r\n" );
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document.write( "so the answer is 11 terms.\r\n" );
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document.write( "Checking: 19+16+13+10+7+4+1-2-5-8-11 = 44\r\n" );
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document.write( "Edwin

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