What is cosine of 8pi/3

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

If a flying disk is 139 meters in the air and travels at an average of 13 m/s how long is it in the air