okay so this question really confuses me, i've tried somesearching around all over the internet, and haven't been able tofind much information on it. So what constitutes a context-freelanguage in the first place?

Then please give me a language that is context free, and then -Lthat same language making it not context free. and vice versa forthe second question.

I have tried doing some digging and if found this similarquestion posted but the answer goes on and on about pumping lemma,except the answer never bothers to give an answer.

is there any way to just glance at a language given and know /kind of tell quickly like judge if its context free or not? bylanguages i mean for example: L1 = { a^n b^n c^n | n>=1 }

please and many thanks!!!

12. (5 points) Give a language L that is a context-free language where -L is not context- free. 13. (5 points) Give a language L that is a context-free language and where -L is also context-free.