The first thing to do is to graph both equations, as follows:
It is possible to check from the equations that there is no restriction for the value of x in both equations, and from the graph, we see that for each value of x, there is always a value of Y well defined. For this reason, we are able to conclude that the domain of both equations is all the real numbers.
Now, for the range of each, we can see that the values of Y for both are restricted to real numbers higher than the minimum value. For equation g(x), the range is the real numbers higher or equal to -3, while for f(x) the range is the real numbers higher or equal to 0.