Answer:
[tex]9d^3[/tex]
Step-by-step explanation:
[tex]~~~\sqrt{81 d^6}\\\\=\left(81 d^6 \right)^{\tfrac 12}\\\\=\left(81\right)^{\tfrac 12} \cdot \left(d^6 \right)^{\tfrac 12}\\\\=\left(9^2 \right)^{\tfrac 12} \cdot d^{\tfrac 62}\\\\=9d^3[/tex]
