$($a$)$ Find $\frac{dy}{dx}$ expressed as a function of $t$ for the given the parametric equations:

$x=2t+lnt$

$y=5t-lnt$

$\frac{dy}{dx}=\frac{5-\frac{1}{t}}{2+\frac{1}{t}}$

$($b$)$ Find $\frac{d^{2}y}{d{x}^2}$ expressed as a function of $t.$

$\frac{d^{2}y}{d{x}^2}=$