document.write( "Question 621645: find sum of series a - (a + d) + (a + 2d) - (a + 3d) + ----- (2n + 1) terms \n" ); document.write( "
Algebra.Com's Answer #390872 by lynnlo(4176)\"\" \"About 
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-2d+2n+1 \n" ); document.write( "
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