document.write( "Question 1091746: Find the sum of the first 30 terms of the arithmetic sequence : 10,5,0,-5 \n" ); document.write( "

Algebra.Com's Answer #706210 by Boreal(15235) $\"\"$ $\"About$

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sum is (n/2)(a1+an)
\n" ); document.write( "a1=10
\n" ); document.write( "an is a1+(n-1)d
\n" ); document.write( "a1=10
\n" ); document.write( "n-1=29
\n" ); document.write( "d=-5
\n" ); document.write( "a30=10+29(-5)=-135
\n" ); document.write( "S=(30/2)(10-135)=15(-125)=-1875
\n" ); document.write( "10
\n" ); document.write( "5
\n" ); document.write( "0
\n" ); document.write( "+ terms are +15
\n" ); document.write( "-5
\n" ); document.write( "-10
\n" ); document.write( "-15
\n" ); document.write( "-20
\n" ); document.write( "-25
\n" ); document.write( "-30
\n" ); document.write( "-35
\n" ); document.write( "-40
\n" ); document.write( "-45
\n" ); document.write( "-50
\n" ); document.write( "-55
\n" ); document.write( "-60
\n" ); document.write( "-65
\n" ); document.write( "-70
\n" ); document.write( "-75
\n" ); document.write( "-80
\n" ); document.write( "-85
\n" ); document.write( "-90
\n" ); document.write( "-95
\n" ); document.write( "-100
\n" ); document.write( "-105
\n" ); document.write( "-110
\n" ); document.write( "-115
\n" ); document.write( "-120
\n" ); document.write( "-125
\n" ); document.write( "-130
\n" ); document.write( "-135
\n" ); document.write( " \n" ); document.write( "

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