Step-by-step explanation:
[tex](6i)^3\qquad\text{use}\ (ab)^n=a^nb^n\\\\=6^3i^3\\\\\text{If}\ i=\sqrt{-1},\ \text{then}\\\\6^3i^3=216(-i)=-216i\\\\\text{else}\\\\6^3i^3=216i^3[/tex]
