Your international diplomacy trip requires stops in thailand, singapore, hong kong, laos, and bali. how many possible itineraries are there? hint [see examples 1 and 2.]

Consider u = {x|x is a negative real number}which is an empty set? o {x|x eu and x has a negative cube root}o {x|x eu and x has a negative square root}{x|x eu and x is equal to the product of a positive number and -1}{x|x eu and x is equal to the sum of one negative and one positive number?