SOLUTION: Evaluate. For a certain arithmetic series, S4=50 and S5=75. Find the first five terms. I know the answer to this question is -25, 0, 25, 50, and 75, but I have to show my wor

Algebra ->  Sequences-and-series -> SOLUTION: Evaluate. For a certain arithmetic series, S4=50 and S5=75. Find the first five terms. I know the answer to this question is -25, 0, 25, 50, and 75, but I have to show my wor      Log On


   

Question 137667This question is from textbook Algebra 2
: Evaluate.
For a certain arithmetic series, S4=50 and S5=75. Find the first five terms.
I know the answer to this question is -25, 0, 25, 50, and 75, but I have to show my work and i'm not sure how i should do this. Can u help?
Thanx. This question is from textbook Algebra 2

Answer by oscargut(2103) About Me  (Show Source):
You can put this solution on YOUR website!
Sn=kn+so
S5-S4=k=75-50=25
then Sn=25n+ao
S4=100+ao=50
then ao=-50
then Sn=25n-50
then So=-50, S1=-25,S2=0,S3=25,S4=50