Which property tells us to multiply the powers to simplify

There are a couple of operations you can do on powers
We can multiply powers with the same base
x4⋅x2=(x⋅x⋅x⋅x)⋅(x⋅x)=x6
xa⋅xb=xa+b
This is an example of the product of powers property tells us that when you multiply powers with the same base you just have to add the exponents

Number 5 is 50 degreesnumber 6 is 45 degreesnumber 7 is 60 degreesnumber 8 is 45 degrees