HELP ME OUT GUYS Question is in the screenshot below.

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

What is the solution to the division problem below x3+x2-11x+4/x+4

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )