Question

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

Answer 1

f(n) = f(n+1) +3 f(1) = f(2) +3 f(2) =f(3) +3 f(3) = f(4) +3 f(1) = f(n) + 3 × (n-1) Substitute n=4 f(1) = f(4) + 3* 3 22 +9 = 31  Thanks  

Answer 2

Given = f(4)=22
So the answer is f(1)=31