document.write( "Question 354641: the first difference of a sequence is 2, 3, 4, 5,... The sum of the first two terms of the original sequence is 16. What first three terms of original sequence? \n" ); document.write( "
Algebra.Com's Answer #253378 by Edwin McCravy(20059)\"\" \"About 
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the first difference of a sequence is 2, 3, 4, 5,... The sum of the first two terms of the original sequence is 16. What first three terms of original sequence?
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document.write( "We have this information.  Put blanks for the unknown values:\r\n" );
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document.write( "n  an  1st diffs   \r\n" );
document.write( "1  a1                   \r\n" );
document.write( "           2\r\n" );
document.write( "2  a2                  \r\n" );
document.write( "           3\r\n" );
document.write( "3  __                  \r\n" );
document.write( "           4\r\n" );
document.write( "4  __                   \r\n" );
document.write( "           5\r\n" );
document.write( "5  __\r\n" );
document.write( "           6\r\n" );
document.write( "6  __    \r\n" );
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document.write( "The sum of the first two terms of the original  sequence is 16\r\n" );
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document.write( "so a1 + a2 = 16\r\n" );
document.write( "and the difference of a2 - a1 is 2\r\n" );
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document.write( "So we have the system:\r\n" );
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document.write( "\"system%28a%5B1%5D%2Ba%5B2%5D=16%2Ca%5B2%5D-a%5B1%5D=2%29\"\r\n" );
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document.write( "So solve that system of equations and get \r\n" );
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document.write( "\"a%5B1%5D=7\" and \"a%5B2%5D=9\"\r\n" );
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document.write( "So we fill those in:\r\n" );
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document.write( "n  an  1st diffs   \r\n" );
document.write( "1   7                   \r\n" );
document.write( "           2\r\n" );
document.write( "2   9                  \r\n" );
document.write( "           3\r\n" );
document.write( "3  __                  \r\n" );
document.write( "           4\r\n" );
document.write( "4  __                   \r\n" );
document.write( "           5\r\n" );
document.write( "5  __\r\n" );
document.write( "           6\r\n" );
document.write( "6  __\r\n" );
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document.write( "Then we can fill in all the other blanks by adding the\r\n" );
document.write( "next difference.\r\n" );
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document.write( "\"a%5B3%5D=9%2B3=12\"\r\n" );
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document.write( "\"a%5B4%5D=12%2B4=16\"\r\n" );
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document.write( "\"a%5B5%5D=16%2B5=21\"\r\n" );
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document.write( "\"a%5B6%5D=21%2B6=27\"\r\n" );
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document.write( "Edwin
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