I won't study without you.
I can't finish this project without you.
Don't eat without me.
There is no way to do this without taking risks.
I didn't play this game without him.
When I see sentences like these, I usually just cancel out the "not"/"no" and "without" and form a positive meaning. But I'm not sure if that's the right way to think because in some cases the meaning can change completely. What does using the 2 words mean exactly and why is it used like this? Some more examples would be nice too.