Which of the following equations have exactly one solution?

The hawaiian alphabet has 12 letters. how many permutations are posible for each number of letters?

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =

Askate shop rents roller skates as shown on the table below. which graph and function models this situation?