How to calculate employees share of taxes for first quarter?

Plz which expression is equivalent to the expression below?

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

Dexter read 11 science fiction books and 5 history books. lena read 9 science fiction books and 4 history books. compare the students’ ratios of science fiction books to history books. 1. determine the ratios’ form:    science fiction books to history books 2. write the ratios as fractions:    dexter: 115; lena: 94 3. rewrite with a common denominator. 4. compare. 5. answer the question. determine which shows the correct comparison of the ratios for this problem.