Which relations represent a function

Graph g(x)=2cosx . use 3.14 for π . use the sine tool to graph the function. graph the function by plotting two points. the first point must be on the midline and closest to the origin. the second point must be a maximum or minimum value on the graph closest to the first point.

On friday, there were x students at the baseball game. on monday, there were half as many students at the game as there were on friday. on wednesday, there were 32 fewer students at the game as there were on friday. which expression could represent the total number of tickets sold for all 3 games?

While on a train trip, marsha noticed that there were 35 people in her train car. after the next stop, there were only 21 people in her car. if p represents the percent decrease in the number of people in marsha's train car, what is p?