A power is two numbers that one is the base and the other is the power.
To calculate a power fraction, both the numerator and the denominator are multiplied the same, so:
[tex]\boldsymbol{\sf{\left(\dfrac{5}{6}\right)^{2}=\dfrac{5\times5}{6\times6}=\dfrac{25}{36} }}[/tex]
Since the fraction 25/36 does not have a half, that is, it is already in reduced form, so it is no longer possible to simplify it.