To apply the property of negative integer exponents and generate an equivalent expression with positive exponents, we can use the following rule:
\[ a^{-n} = \frac{1}{a^n} \]
Given the expression \( 7^{-3} \times 7^{-5} \), we first apply the property of exponents that states:
\[ a^m \times a^n = a^{m+n} \]
So, for our expression:
\[ 7^{-3} \times 7^{-5} = 7^{-3 + (-5)} = 7^{-8} \]
Now, we can express \( 7^{-8} \) using positive exponents:
\[ 7^{-8} = \frac{1}{7^8} \]
Thus, the equivalent expression with positive exponents only is:
\[ \frac{1}{7^8} \]