Check out the exponent rules if you can, i'm not too clear on what the first part of your question is (a)8? You may need to provide some more information on that
But your second question is all about exponential rules. Remember x3 is the same as (x*x*x)
so (x3)2 can be written as (x*x*x)(x*x*x) which is x6 , know that if a function has an exponent on the outside of the parenthesis you can multiply it, to save time, (x3)2 , 3*2= 6, so x6
Looking at your problem, it can written as (4y3)(4y3) which would be equal to
You should definitely check out exponent rules if you can, to clear up any confusion.
Hope this helps you!