The Product Rule of Exponents states that when two numbers with the same base are multiplied, you can keep the base and add the exponents.
In this case, we have 5^10 multiplied by 5^5. Since the base is the same (5), we keep the base and add the exponents:
5^10 x 5^5 = 5^(10 + 5) = 5^15
So, 510 x 55 simplifies to 5^15.