Question

f(1)=9 and f(n)=3f(n-1)-5 then find f(5)

Answer 1

Answer:

f(5)=529

Step-by-step explanation:

$f(1)=9\\\\f(n)=3f(n-1)-5\\\\n=5\\\\f(5)=3f(5-1)-5\\\\f(5)=3f(4)-5$

we can start by finding f(2)

$f(2)=3f(2-1)-5\\\\f(2)=3f(1)-5\\\\f(2)=3(9)-5\\\\f(2)=27-5\\\\f(2)=22$

we can go to f(3)

$f(3)=3f(3-1)-5\\\\f(3)=3f(2)-5\\\\f(3)=3(22)-5\\\\f(3)=66-5\\\\f(3)=61$

we can go to f(4)

$f(4)=3f(4-1)-5\\\\f(4)=3f(3)-5\\\\f(4)=3(61)-5\\\\f(4)=183-5\\\\f(4)=178$

so we can find f(5)

$f(5)=3f(4)-5\\\\f(5)=3(178)-5\\\\f(5)=534-5\\\\f(5)=529$