Question 1: (25 pts.) [5 points each] Find the limit of the following expressions (if they exist); simplify completely your final answer and show all work and steps. Results given

without any justifications will not receive credits. \text { b) } \lim _{x \rightarrow 0}\left(\frac{3 x}{\frac{1}{x+3}-\frac{1}{3}}\right)