Help please! I think the answer is obvious, but my brain is fried and I probably tried all of the wrong things!

Which of the following of the following sets of side lengths could not form a triangle?

Which function has the same domain as y=2x

10 ! a train starts from grand city and travels toward belleville 388 miles away. at the same time, a train starts from belleville and runs at the rate of 47 miles per hour toward grand city. they pass each other 4 hours later. find the rate of the train from grand city.