Applicare la formula: $a^n$$=\left(-a\right)^ni$, dove $a^n=\sqrt[4]{-9}$, $a=-9$ e $n=\frac{1}{4}$

Applicare la formula: $\left(ab\right)^n$$=a^nb^n$, dove $a=\sqrt[4]{9}$, $b=i$ e $n=\frac{1}{3}$

Applicare la formula: $\left(x^a\right)^b$$=x^{ab}$, dove $a=\frac{1}{4}$, $b=\frac{1}{3}$, $x^a^b=\sqrt[3]{\sqrt[4]{9}}$, $x=9$ e $x^a=\sqrt[4]{9}$