Answer:
10x+30
Explanation:
Distributive property is distributing what is in the parentheses.
To do that on this problem you have multiply each of these numbers by 10!
10 times x is 10x
10 times 3 is 30
Put them back together and you get 10x+30!
I hope this helps, and have a great day! :)
P.S. If you need a better explanation I can help. I just didn't want to make this to long. :D