Question 619084
 

What  do  you  know  about  negative  exponents?

Do you  remember   that:
2^(-3)  =  1/2^3      so      a^(-3) = 1/a^3 


4a^(-3) ÷  8a^(-6)
=(  4)/a^3   ÷8/a^6    =  4/a^3  (a^6/8)  =  1/2 a^3