Which is the domain for the piece of the function repreented by f(x)=x+1 ?

The domain for the function f(x) = x + 1 would be all real numbers. 

The domain is all real numbers because you could input an value into the equation for x.

However, if you have a graph and the entire line for f(x) = x + 1 is not shown, then you would have to select only the values of x that are shown on the graph.

The graph of f(x) = x + 1 starts at the point (0, 1) and has a slope of 1.