Answer:
You need to replace the x with the value that you want to evaluate. If the initial value is 1, you have to replace the x with1, then with 2, an finally with 3.
Iteration 1.
f(x=1)=3*(1)
f(x=1)=3
Iteration 2.
f(x=2)=3*(2)
f(x=2)=6
Iteration 3.
f(x=3)=3*(3)
f(x=3)=9
