Answer: True
This is a cubic polynomial function. Any polynomial will have a domain of "all real numbers". We do not have to worry about things like division by zero errors, or applying square roots to negative numbers. Any number can replace x to get some output for y = f(x).
When graphing this function, note it stretches forever to the left and right. There aren't any gaps, holes, jumps, etc. It's one continuous S shaped curve. Use a tool like Desmos or GeoGebra to make the graph.