rewrite with positive exponents. Assume that even roots are of nonnegative quantities and that all denominators are nonzero.
[3}^-4
---
ua^2}
3^-4
Multiply numerator and denominator by 3^4:
3^-4 * 3^4 / 3^4= 1/3^4.
[3}^-4
---
ua^2}
Multiply numerator and denominator by 3^4:
3^-4 * 3^4 / 3^4= 1/3^4.