SOLUTION: find a sub 1 if a sub 8=54 and a sub 9=60

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Question 1085514: find a sub 1 if a sub 8=54 and a sub 9=60
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
a%5Bn%5D=a%5B1%5D%2B%28n-1%29%2Ad
So,
a%5B8%5D=a%5B1%5D%2B%288-1%29%2Ad=54
1.a%5B1%5D%2B7d=54
and
a%5B9%5D=a%5B1%5D%2B%289-1%29%2Ad=60
2.a%5B1%5D%2B8d=60
Subtracting 1 from 2,
a%5B1%5D%2B8d-a%5B1%5D-7d=60-54
d=6
So then,
a%5B1%5D%2B7%286%29=54
a%5B1%5D%2B42=54
Now solve for a%5B1%5D.