first of all, you need to understand that _/x = x^(1/2
3_/6^(6 should be written as 6^(6/3 in the next step, in the first step the square root should be gone already,thus she had made a mistake in step A.
here's a formula to help you understand
![√(2) = {2}^{ (1)/(2) } \\ \\ \sqrt[3]{ {6}^(6) } \\ = {6}^{ (6)/(3) } \\ = {6}^{ (1)/(2) } \\ = √(6)](https://img.qammunity.org/2019/formulas/mathematics/high-school/bcqvju55so25zhgyjhoxb7beo3ajrfcmyg.png)
hope it helps!