Solve 3x+1 = 15 for x using the change of base formula

What are the steps to solving the inequality 3b + 8 ≥ 14?

Inez has a phone card. the graph shows the number of minutes that remain on her phone card a certain number of days.

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.