Which is the best estimate for the average rate of change for the quadratic function graph on the interval −12 ≤ x ≤ −4?

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

Plzzz answer both questions and i will give you 100 points

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]