Solution:
[tex]\large\tex\text{Given expression:} \huge\tex\text{[}\dfrac{5^{-2} }{2^{3} } \huge\tex\text{]}^{4}[/tex]
Since the exponents inside the brackets do not have any relation (Not through bases, nor through exponents), we will need to simplify the exponents.
1. Simplifying the exponents inside the bracket:
[tex]\bullet \ \rightarrow \huge\tex\text{[}\dfrac{5^{-2} }{2^{3} } \huge\tex\text{]}^{4}[/tex]
[tex]\bullet \ \rightarrow \huge\tex\text{[}\dfrac{\frac{1}{5^{2} } }{2 \times 2 \times 2} \huge\tex\text{]}^{4}[/tex]
[tex]\bullet \ \rightarrow \huge\tex\text{[}\dfrac{\frac{1}{25 } }{8} \huge\tex\text{]}^{4}[/tex]
2. Opening the brackets:
[tex]\bullet \ \rightarrow \huge\tex\text{[}\dfrac{\frac{1}{25 } }{8} \huge\tex\text{]}^{4}[/tex]
[tex]\bullet \ \rightarrow \huge\tex\text{[}\dfrac{\frac{1^{4} }{25^{4} } }{8^{4} } \huge\tex\text{]}[/tex]
[tex]\bullet \ \rightarrow \dfrac{\frac{1^{4} }{25^{4} } }{8^{4} }[/tex]
3. Simplifying the exponents:
[tex]\bullet \ \rightarrow \dfrac{\frac{1^{4} }{25^{4} } }{8^{4} }[/tex]
[tex]\bullet \ \rightarrow \dfrac{\dfrac{1}{390625 } }{4096}[/tex]
[tex]\bullet \ \rightarrow {\dfrac{1}{390625 } \times \dfrac{1}{4096}[/tex]
[tex]\bullet \ \rightarrow \boxed{\bold{\dfrac{1}{1600000000} }}[/tex]