help!

(2^20/2^17)^3=

(3y^6)(8y^-3)=

(4a^3y^-4/2a^5y^-7)65=

I will do one: you need to review the rules.

(2^20/2^17)^3=
(2^[20-17])^3=
(2^3)^3=
(2^9) = calculator