Answer: n,5n and 2n; 2m and 6m.
Are n and n^3 the same? No. They are unlike terms.
Are n and 5n the same? Yes. Because they have n in common.
For question 2, n,5n and 2n all have n in common, so they are like terms. 2m and 6m have m in common therefore, they are like terms.
The answer for no.2 is n,5n and 2n; 2m and 6m.
Note:PLEASE don't just take this answer and do it without understanding. I want you to understand the concept and then you can truly thrive.