[(25^1/10)(36^-1/10)]^5
When you have an exponent to an exponent, multiply the exponents together.
25^(1/10) = (5^2)^(1/10) = 5^(1/5)
36^(-1/10) = (6^2)^(-1/10) = 6^(-1/5)
[5^(1/5)·6^(-1/5)]^5 = [5·(1/6)] = 5/6