Thank you for the opportunity to help you with your question! Hope your day is going well!

This is a law of exponents problem. When a variable(or number) have the same base (i.e y in this problem), were are allowed to combine the exponents. By laws of exponents, when we multiply the same base with their exponents, we add the exponents.

y^6 * y^7

y^(6+7)

y^13.

For example

2^6 * 2^7=8192

Use the laws of exponents to see if you get the same answer

2^(6+7)

2^13= 8192.

check! We get the same answer.

Please let me know if you need any clarification. I'm always happy to answer your questions. Leave a positive review if you are happy!