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A sequence is defined by the formula f(n+1)=f(n)-3. If f(4)=22, what is f(1)?

A. 10
B. 13
C. 31
D. 34

2 Answers

3 votes

Answer:

31

Explanation:

User MikeRalphson
by
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5 votes

9514 1404 393

Answer:

C. 31

Explanation:

The recursive definition tells us the 4th term is 22 and the common difference is -3. This lets us write an explicit formula for the n-th term:

f(n) = f(4) +d(n -4)

f(n) = 22 -3(n -4) = 34 -3n

Substituting n=1 into this formula, we get ...

f(1) = 34 -3(1) = 31

The first term is f(1) = 31.

User Rossco
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