Which is the graph of f(x) = 3 (3/2)^x ?

The graph of the function f(x) is:

                      Graph  4

We are given a function f(x) in terms of variable x as follows:

Now, when x=0 then the graph of the function f(x) must pass through:

and when x=1 then the graph of the function f(x) must pass through:

i.e. the graph of the function should pass through the points:

(0,3) and (1,2)

Now, after looking at the graph we observe that the first and second graph do  not pass through (0,3).

Hence, graph 1 and graph 2 do not represent the function f(x).

Also, graph 3 pass through (0,3) but it does not pass through (1,2)

Hence, Graph 3 does not represent f(x)

Hence, the correct graph is: Graph 4