13^-5 x 13^-11 with postive exponents only
When multiplying expressions with the same base and different exponents, you add the exponents together.
So, 13^-5 x 13^-11 can be simplified as 13^(-5 + -11).
Adding -5 and -11 gives you -16.
Therefore, 13^-5 x 13^-11 simplifies to 13^-16.