Question 862179
Domain is the set of all values for x.
So you have to substitute -1,0,1 and 2 for x in the given expression and evaluate the result.

f(x) = 3^x

f(-1) = 3^(-1)
      =1/3
f(0) = 3^(0)
     =1
f(1) = 3^1
     =3
f(2) = 3^2
     =9