SOLUTION: i cant figure out these problems 27. 75 sigma n=21 (2n+5) i solved this problem using the formula Sn=n/2(a1+an) and i got 5454 when the answer in the back was 5555. what did i d

Algebra ->  Sequences-and-series -> SOLUTION: i cant figure out these problems 27. 75 sigma n=21 (2n+5) i solved this problem using the formula Sn=n/2(a1+an) and i got 5454 when the answer in the back was 5555. what did i d      Log On

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 Click here to see ALL problems on Sequences-and-series Question 134757This question is from textbook merrill algebra 2 with trigonometry applications and connections : i cant figure out these problems 27. 75 sigma n=21 (2n+5) i solved this problem using the formula Sn=n/2(a1+an) and i got 5454 when the answer in the back was 5555. what did i do wrong 31. d=5, n=16, an=72 find Sn for the sequence how do you get a1 help me solve these plese This question is from textbook merrill algebra 2 with trigonometry applications and connections Answer by vleith(2950)   (Show Source): You can put this solution on YOUR website! Don't know on the first one, but to get the a1 in the second one 72 = a1 + (n-1)d