Final answer:
The expression 16c−4d^3 is already simplified because it does not contain like terms or negative exponents.
Step-by-step explanation:
To simplify the expression 16c−4d^3, we observe that there are no like terms to combine since c and d are different variables.
Therefore, the expression is already in its simplest form, and there is no further simplification that can be done.
It is important to note that the expression does not have any negative exponents, and we do not need to operate with the exponents in any way for this particular simplification task.