(n^3)^2*(n^5)^4
The laws of exponents states that when raising a power by a power, then you must multiply. This law gets rid of the exponents outside of the parenthesis.
n^6 * n^20
Another law states that when multiplying variables with exponents, then you must add the exponents together. That leaves you with this as your answer.
n^26
Hope this helps!