For the following function, $($a$)$ find the critical points and $($b$)$ find absolute minimum and maximium.

$f(x)=-x^{2}2x4,[-3,2].$

Find $\frac{dy}{dx}$ by differentiating implicitly then find the value of $\frac{dy}{dx}$ at the point. $y^{2}3xy{x}^2=5,(1,1).$