Helppp me im on a test with this question

Can i get some on 18,20,& 22? or one of them

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

Solve the problem. a student earned grades of c, a, b, and a in four different courses. those courses had these corresponding numbers of credit hours: 4, 5, 1, and 5. the grading system assigns quality points to letter grades as follows: a = 4, b = 3, c = 2, d = 1, and f = 0. compute the grade point average (gpa) and round the result to two decimal places. 3.40 3.50 8.75 2.18