I'm doing my math homework and I don't understand multiplying exponents. My book says the answer is 1/x^15 but I don't understand how to get that answer.

The best way to think about these problems is to remember what happens when you have x^-1. This is the same thing 1/x. Technically speaking x^-1 is the same as (x^1)^-1. So think about it like we put 1 x^1 in the denominator. Now if we look at this problem it has (x^3)^-5. So we would multiply 5 x^3 in the denominator and get 1/x^15. Hope this helps. Feel free to message me with any other questions