생활 and 인생.. what are the differences?
I use 인생 when I say.. "인생 힌들어요" in what situation I can use 생활?

Question

생활 and 인생.. what are the differences?
I use 인생 when I say.. "인생 힌들어요"  in what situation I can use 생활?

Answer

인생 all of my life, like from birth to death.  
생활 is life to live.   Way to live.
생활이 함들어요  means nowadays coz of money or friends,its not easy to maintain my life,
인생이 힘들어요 means my  life (from birth to death , or could be destiny) is too tough.

Answer

What Sujin said.

But, for exaggeration, you can say "인생이 힘들어요." to mean "생활이 힘들어요."
Also it's useful to know  that "인생이" often collocates with "고달프다"