I'm new to factoring. Don't really understand the definition of "prime". I did 47 questions in my homework, but I want to make sure if some are right or wrong.

I will answer the questions. Tell me if they are right/ wrong. If they are wrong, then tell me how. At least show me some type of work , so I understand.

1) P^4-49= (P^2+7)(P^2-7)

2) X^4-1 = (X^2+1)(X^2-1)

(X^2-1) can be factored into (X+1) (X-1).

Total answer: (X^2+1)(X+1)(X-1)

3) 100x^2+49= PRIME

4) K^2-18= PRIME

5) 81W^2+16= Prime

6) 6t^3-2= Prime

7) M^2-12= Prime

I think I have a problem with primes, because it seemed weird I had too many primes.

Help me , please