Final answer:
The domain of the polynomial function f(x) = -2x(x-1)(x-5) is all real numbers, which means any real number can be substituted for x.
Step-by-step explanation:
The domain of a function consists of all the values that x can take for which the function is defined. For the given function f(x) = -2x(x-1)(x-5), it is a polynomial function. Polynomial functions are defined for all real numbers; therefore, the domain of this function is all real numbers. This can be indicated by the expression -∞ < x < ∞, where ∞ represents infinity.