1. The problem asks about the type of numbers that are all in the x-coordinates of an exponential function. 2. An exponential function is generally written as $$y = a^x$$ where $$a > 0$$ and $$a \neq 1$$. 3. In this function, $$x$$ is the exponent and it can be any real number. 4. This means the x-coordinate is not limited to rational numbers, integers, natural numbers, or whole numbers. 5. The x-coordinates of an exponential function are actually **all real numbers** because the function is defined for every real value of $$x$$. 6. Therefore, it is incorrect to classify all x-coordinates as any subset like rational, integer, natural, or whole numbers since it includes irrational numbers as well. Final answer: The x-coordinates of an exponential function are all real numbers, not limited to the categories listed.