Answer:
The domain of the graph is,

Explanation:
The domain is the interval of values for which the function is defined.
We see that for all values of x, the function is defined
(e.g for x = 0 f(0) = 3 and so on)
and we see that it is defined for negative as well as positive values of x.
Hence the domain will be,

The domain is from negative infinity to positive infinity