Can I get help with this

Which of the following are accepted without proof in a logical system? check all that apply.

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

You have 12 balloons to blow up for your birthday party. you blow up 1/3, and your friend blows up 5 of them. what fraction of the baloons still need blowing up