Answer :
Given:
[tex]f(1)=7[/tex]
[tex]f(n)=3f(n-1)+3[/tex]
To find:
The value of f(3).
Solution:
We have,
[tex]f(n)=3f(n-1)+3[/tex] ...(i)
Substituting [tex]n=2[/tex] in (i), we get
[tex]f(2)=3f(2-1)+3[/tex]
[tex]f(2)=3f(1)+3[/tex]
Substituting [tex]f(1)=7[/tex] in the above equation, we get
[tex]f(2)=3(7)+3[/tex]
[tex]f(2)=21+3[/tex]
[tex]f(2)=24[/tex]
Now, substituting [tex]n=3[/tex] in (i), we get
[tex]f(3)=3f(3-1)+3[/tex]
[tex]f(3)=3f(2)+3[/tex]
Substituting [tex]f(2)=24[/tex] in the above equation, we get
[tex]f(3)=3(24)+3[/tex]
[tex]f(3)=72+3[/tex]
[tex]f(3)=75[/tex]
Therefore, the value of f(3) is 75.