Help please Im tAking a test

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

Need ! give step by step solutions on how to solve number one [tex]\frac{9-2\sqrt{3} }{12+\sqrt{3} }[/tex] number two [tex]x+4=\sqrt{13x-20}[/tex] number three (domain and range) [tex]f(x)=2\sqrt[3]{x} +1[/tex]

What is the ordered pair of m’ after point m (5, 6) is rotated 90° counterclockwise?