Question

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

-10
-O13
-31
-34

Answer 1

Answer: 31

Explanation:

If n=3,
`f(4)=f(3)-3 \longrightarrow 22=f(3)-3 \longrightarrow f(3)=25`

If n=2,
`f(3)=f(2)-3 \longrightarrow 25=f(2)-3 \longrightarrow f(2)=28`

If n=1,
`f(2)=f(1)-3 \longrightarrow 28=f(1)-3 \longrightarrow f(1)=\boxed{31}`