We will use the following law of indices (or 'index law') to check each pair of expression
![x^{ \frac{m}{n}} = ( \sqrt[n]{x} )^{m}](https://tex.z-dn.net/?f=%20x%5E%7B%20%5Cfrac%7Bm%7D%7Bn%7D%7D%20%3D%20%28%20%5Csqrt%5Bn%5D%7Bx%7D%20%29%5E%7Bm%7D%20)
With fractional power, the denominator is the root and the numerator is the power of the term. When the denominator is 2, we usually only write the normal square symbol (√). Denominator other than 2, we usually write the value of the root, for example, the cubic root ∛
Option A - Incorrect
should equal to ![( \sqrt[7]{7} )^{5}](https://tex.z-dn.net/?f=%20%28%20%5Csqrt%5B7%5D%7B7%7D%20%29%5E%7B5%7D%20)
Option B - Correct
does equal to 
Option C - Incorrect
should equal to 
Option D - Incorrect
should equal to ![( \sqrt[3]{5} )^{2}](https://tex.z-dn.net/?f=%20%28%20%5Csqrt%5B3%5D%7B5%7D%20%29%5E%7B2%7D%20)
With fractional power, the denominator is the root and the numerator is the power of the term. When the denominator is 2, we usually only write the normal square symbol (√). Denominator other than 2, we usually write the value of the root, for example, the cubic root ∛
Option A - Incorrect
Option B - Correct
Option C - Incorrect
Option D - Incorrect