Please give me the correct answer

?: a^2,b^2,or c^2

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

How many solutions does the nonlinear system of equations graphed below have? a. one b. zero c. four d. two

Harry the hook has 7 1/3 pounds of cookie dough.she uses 3/5 of it to bake cookie. how much cookie dough does she use to make cookie?