Your doing the Distributive Property. So in this equation your distributing the first 2 on the outside of the parenthesis, so this first section of your problem after distributing is 6n+8. Next distribute the -2 to the 2n and 5. DON'T FORGET THE NEGATIVE. So it would look like 6n+8-4n-10. Then combine like-terms. so 6n-4n = 2n. Then 8-10=-2. Your final answer should be
2n-2.
Hope this helped.