4. Tim's family just got back from a vacation. They had been traveling for 2 days, driving 11 hours each day. How many hours altogether were they in the car?

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?