To divide the rational numbers \(-91\) by \(-13\), you perform the following calculation:
\[ \frac{-91}{-13} \]
Since both numbers are negative, their signs will cancel out, resulting in a positive quotient:
\[ \frac{91}{13} \]
Now, you can simplify this fraction or convert it to a mixed number:
\[ 91 \div 13 = 7 \quad \text{remainder } 0 \]
Thus, \(\frac{91}{13} = 7\).
So, the final answer is:
\[ 7 \]