document.write( "Question 1053181: Find the sum of -1+2+5+...+(3n-4)
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Algebra.Com's Answer #668413 by ikleyn(52798)\"\" \"About 
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\n" ); document.write( "Apply the formula for the sum of an arithmetic progression.\r
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\n" ); document.write( "\n" ); document.write( "First term is -1, the common difference is 3, the number of terms is n.\r
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\n" ); document.write( "\n" ); document.write( "See the lessons \r
\n" ); document.write( "\n" ); document.write( "    - Arithmetic progressions\r
\n" ); document.write( "\n" ); document.write( "    - The proofs of the formulas for arithmetic progressions \r
\n" ); document.write( "\n" ); document.write( "    - Problems on arithmetic progressions \r
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