To express \( \frac{7^3}{25^{-4}} \) with only positive exponents, we can use the property of negative integer exponents, which states that \( a^{-n} = \frac{1}{a^n} \).
Starting with the expression:
\[ \frac{7^3}{25^{-4}} \]
We can apply the property of negative exponents:
\[ = 7^3 \cdot 25^{4} \]
This is because \( \frac{1}{25^{-4}} \) is equivalent to \( 25^4 \).
Thus, the equivalent expression with only positive exponents is:
\[ 7^3 \cdot 25^4 \]
The correct answer is:
\[ 7^3 \cdot 25^4 \]