Simplify using the law of exponents,where n is the positive integer.

1)x^n . x^2n

attempt

x^n+2n = x^3n

2)(x^n)^3n

attempt

x^n*3n =x^3n^2

3)(x^3+n)(x^3n-1)

attempt

I dont't know how to do it

Please tell me if my attempt are wrong and if they are please write in step so I can properly understand.

Thank you,