document.write( "Question 929332: please help me find the sum of the following sequence (-6)+(-1)+4+9+...+39 thank you \n" ); document.write( "

Algebra.Com's Answer #564202 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
First find the sequence.
\n" ); document.write( " $\"a%5Bn%5D=-11%2B5n\"$
\n" ); document.write( "Then find n for the last term.
\n" ); document.write( " $\"39=-11%2B5n\"$
\n" ); document.write( " $\"50=5n\"$
\n" ); document.write( " $\"n=10\"$
\n" ); document.write( "Then use the sum formula,
\n" ); document.write( " $\"S%5Bn%5D=%28n%2F2%29%28a%5B1%5D%2Ba%5Bn%5D%29\"$
\n" ); document.write( " $\"S%5B10%5D=%2810%2F2%29%28-6%2B39%29\"$
\n" ); document.write( " $\"S%5B10%5D=5%2833%29\"$
\n" ); document.write( " $\"highlight%28S%5B10%5D=165%29\"$
\n" ); document.write( " \n" ); document.write( "

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