Here is how we do it:
First, we must simplify 4/5n to 4n/5.
Then we simplify:
to get

After we multiply both sides by the number 15.

Alright, now let's move them all together.
It would be:

Our last step is to simplify 12n - 10n to 2n.
Then we receive:

After we divide both sides by 2.
Our final answer is: