Let a and b be numbers such that a^3=5 and b^3=4. Find the value of (ab^2)^{-3}.

(ab^2)^{-3} = 16/5

a^3 ==5, solve for a

a ==1.71

b^3 ==4, solve for b

b=1.587

{ [1.71*1.587]^2 }^ - 3 =={0.00250358}