Answer:
[tex]\large\boxed{\dfrac{1}{625t^{12}}}[/tex]
Step-by-step explanation:
[tex](5t^3)^{-4}\qquad\text{use}\ a^{-n}=\dfrac{1}{a^n}\\\\=\dfrac{1}{(5t^3)^4}\qquad\text{use}\ (ab)^n=a^nb^n\\\\=\dfrac{1}{5^4(t^3)^4}\qquad\text{use}\ (a^n)^m=a^{nm}\\\\=\dfrac{1}{625t^{(3)(4)}}=\dfrac{1}{625t^{12}}[/tex]
