How many units are in between the distance of (−4, 9) and (−4, 3)? How many units are in between the distance (−4, 9), (−4, 3), and (1, 3)?

How many units are in between the distance (−4, 9), (−4, 3), and (−4, −8)?

Thank you!

nobody answered my last one lol, you aren't required to answer all of these I guess but at least one would be a big help!

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.