8friends share 12 pies how many pies does each friend get

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

Write two subtraction equations that are equivalent to 5 + 12 = 17.

Can someone plz me understand how to do these. plz, show work.in exercises 1-4, rewrite the expression in rational exponent form.[tex]\sqrt[4]{625} \sqrt[3]{512} (\sqrt[5]{4} )³ (\sqrt[4]{15} )^{7}\\ (\sqrt[3]{27} )^{2}[/tex]