You could use a couple properties of exponents.
Here's a similar example that shows how.
(a^7 * b^15)/(a*b)^3
In the denominator, both of the factors (a and b) get cubed. That's according to this property:
(xy)^n = x^n * y^n
(a^7 * b^15)/(a^3 * b^3)
We can factor this ratio into a product of two ratios where the bases are the same in the numerator and denominator.
a^7/a^3 * b^15/b^3
Now, we can use another property of exponents, since the bases are the same on top and bottom, in each ratio of powers above. Here's the property.
a^n/a^m = a^(n - m)
In other words, when the bases are the same in a ratio of powers, we can subtract the lower exponent away from the upper exponent.
a^(7 - 3) * b^(15 - 3)
a^4 * b^12
Your exercise can be done using the same strategy.
MY EDITS: Corrected two typographical errors, neither of which changes the meaning of my post.