SOLUTION: Consider each given sequence start. i) Classify each as arithmetic, geometric, and/or none of these. ii) Find the 28th term. iii) Find the sum of the first 7 terms, call it S7

Question 1178154: Consider each given sequence start. i) Classify each as arithmetic, geometric, and/or none of these. ii) Find the 28th term. iii) Find the sum of the first 7 terms, call it S7 .
88,83, 78, 73,
Found 2 solutions by mananth, MathLover1:
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!

88,83, 78, 73,
common difference between consecutive terms is -5
first term a = 88
tn = a + (n-1)*d
t28 = 88+(87)*-5
t28 = -347
Sum of terms = Sn = n/2(2a+(n-1)d)
S7 = (7/2)(2*88+ 6*-5)
S7 =(7/2) * 146
S7 =511

Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!

,, , ,...
1st term
2nd term
3rd term
=> common difference is

i) Classify each as arithmetic, geometric, and/or none of these.
=> common difference is , so you have an arithmetic sequence
th term formula will be:

ii) Find the th term.

iii) Find the sum of the first terms, call it .
first find th, th, and th term

,, , ,,,

the sum is

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