You can put this solution on YOUR website! This demonstrates the first basic exponent rule: Whenever you multiply two terms with the same base, you can add the exponents:
(x^m)*(x^n) = x^(m+n)
So in this problem:
(5^-8)*(5^10)=
5^(-8+10)=
5^(2)=
25
Your answer is 25.