b$)$ If

$y=4e^{-2x}-8e^{3x}$

i$)$ Find $\frac{dy}{dx}$ and $\frac{d^{2}y}{d{x}^2}$

$[2]$

ii$)$ Hence find the value of $\frac{d^{2}y}{d{x}^2}-\frac{dy}{dx}+y$ when $x=ln(\frac{1}{2})$

$[2]$