i have no idea what i am doing! pls help!!!

Answer:
The first one
Step-by-step explanation:
If you are adding 15 less to 3 of n, it would be 3n-15 because 3 of n is 3n. After, you add n as well, so you get 3n-15+n. Your result is 101 so it should be on the other side of the equation.