SOLUTION: the fifth and eighth terms of a sequence of real numbers are 7 and 8. What is the first term?

Algebra ->  Sequences-and-series -> SOLUTION: the fifth and eighth terms of a sequence of real numbers are 7 and 8. What is the first term?      Log On


   

Question 900663: the fifth and eighth terms of a sequence of real numbers are 7 and 8. What is the first term?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Many possible solutions. What kind of sequence?

T=F+(n-1)d, general term for arithmetic sequence.
F, first term
n, index of sequence
d, common difference

system%28F%2B%285-1%29d=7%2CF%2B%288-1%29d=8%29
system%28F%2B4d=7%2CF%2B7d=8%29
3d=1
d=1%2F3
F=7-4%2F3
F=21%2F3-4%2F3
highlight%28highlight%28F=17%2F3%29%29----the first term

highlight%28T=17%2F3%2B%28n-1%29%2A%281%2F3%29%29---general term for this arithmetic sequence