I'll mark you brainlist

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

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]

Ana’s dachshund weighed 5 5/8 pounds when it was born . by age 4 the dog weighed 6 times as much. fill each box with a number or symbols from the list to show how to find the weight of ana’s dog at age 4 . not all numbers and symbols my be used