What is the simplified form?

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

6.(q^9)^2 a. 2q^18 b. q^18 c. q^81 d.q^11 7.(6q^6)^-4 a. 6q^1296 b. 1296q^2 c. 1/1296q^24 d. 6q^-24 8. what is the value of 12x^-3 y^-1 for x = -1 and y = 5? a. -12/5 b.-10 c.-0 d.5/12

For a field trip to the zoo, 4 students rode in cars and the rest filled nine busess. how many students were in each bus if 472 students were on the trip