Question

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

Answer 1

Answer:

Since f(n + 1) = f(n) - 3, we can also say that f(n - 1) = f(n) + 3.

By which we can say f(n - 3) = f(n) + 9

Since f(4) is 22, then f(1) must be 22 + 9, or 31.