Which of the sets of ordered pairs represents a function?
a = {(1, -2). (3.-5), (5,2), (7,5)}
b = {(4,2), (4, -2), (9,3), (9, -3)}

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

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

An angle that measures between 90 and 180° is called a(,