I need help. This question is due tonight~

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

Type the correct answer in each box. spell all words correctly. a sequence of transformations maps ∆abc onto ∆a″b″c″. the type of transformation that maps ∆abc onto ∆a′b′c′ is a . when ∆a′b′c′ is reflected across the line x = -2 to form ∆a″b″c″, vertex of ∆a″b″c″ will have the same coordinates as b′.

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b