2. ## Re: Need of help

Originally Posted by soso123

3. ## Re: Need of help

R is a ring with 1 and M is a left R-module.

4. ## Re: Need of help

Originally Posted by soso123
R is a ring with 1 and M is a left R-module.
Thank you for the reply. Defining all terms is a good habit to have.

What do you know about $s\cdot 0~?$