SOLUTION: the sum of the first n terms of two A.Ps are as 13-7n:3n+1.find the ratio of their first terms and also of their second terms.

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Question 913253: the sum of the first n terms of two A.Ps are as 13-7n:3n+1.find the ratio of their first terms and also of their second terms.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
S%5Ban%5D=+%28n%28a%5B1%5D%2Ba%5Bn%5D%29%29%2F2+
S%5Bbn%5D=+%28n%28b%5B1%5D%2Bb%5Bn%5D%29%29%2F2+

%28a%5B1%5D%2Ba%5Bn%5D%29%2F+%28b%5B1%5D%2Bb%5Bn%5D%29+=+%2813-7n%29%2F%283n%2B1%29
n = 1
2a%5B1%5D%2F2b%5B1%5D+=+6%2F4 , a%5B1%5D%2Fb%5B1%5D+=+3%2F2
n = 2

a%5B2%5D%2Fb%5B2%5D+=+%28-5%2F2%29%2F6+