For the third question you may want to recall the definition of continuity of a function at a specific point.

For 3.a. you only need to write the definition of continuity itself.

For 3.b. you may find useful to remember the formal definition of a limit for any function. Then, how can you rewrite this definition in epsilon-delta language?

For 3.c. the clue could be starting by writing the formal definition for each condition given at the problem (for example, write the formal definition of the limit for continuity of g(x) at a . Having also the formal definition of a limit in mind, you can relate inequalities each other. You would have to make a relation with the two deltas of the definition.