The function on the left is continuous in the domain show and the one on the right is continuous except at x=0. That means that the requested limits can be found by substitution except at x=0 where you will need to exercise some care in answering.
Remember a function is continuous when lim (as x approaches a) f(x) = f(a).
Therefore when a function is continuous the limit and the value of the function at the the point of the limit are the same!
g(x) will have a left and right sided at 0 limit BUT the limits are NOT equal! Thus at 0 g has a non-removable or jump discontinuity.
If you still don't understand, please comment with a SPECIFIC question. BTW, I will NOT do these problems for you!
