Given $\displaystyle \frac{1}{x}+\frac{1}{y}=3$:
(a) Find $y'$ by implicit differentiation (leave your answer in terms of $x$ and $y$).
(b) Solve the equation for $y$ and differentiate to get $y'$ in terms of $x$.
(The answers should be consistent!)

(a) $y' =$
(b) $y' =$