SOLUTION: Find the sum of the first 12 terms of arithmetic sequence with a common difference of -5 if its 23rd term is 556.

Question 1141173: Find the sum of the first 12 terms of arithmetic sequence with a common difference of -5 if its 23rd term is 556.
Answer by josgarithmetic(39618) (Show Source): You can put this solution on YOUR website!
Common Difference as given

If first term is A, then
AMP Parsing Error of [Common Difference as given

If first term is A, then
]: Invalid expression '/cgi-bin/plot-formula.mpl?expression=-5width=28height=18>asgivenIffirsttermisA,then': syntax error at /home/ichudov/project_locations/algebra.com/templates/Algebra/Expression.pm line 203. . A=666}}
-
12th term is 666-5(11)=500
Sum asked for is (12/2)(666+500) from the summation formula for Arithmetic Series.

6996
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