In the numerator, we apply the power rule for exponents.
The power rule: (x^a)^b = x^(ab)
Then (4x^5)^3 = 4x^(15)...This is our numerator now.
The denominator stays the same.
We now have [4x^(15)]/[(8y^6)] as the final answer.
There is nothing more that can be done to simplify this fraction.