Solve

$\frac{d^{2}i}{d{t}^2}5\frac{di}{dt}4i=12$

If $\frac{di(0)}{dt}=0$ and $i(0)=-1$

Answer:

$i(t)$

$=[3-5\mathrm{.}33e^{-t}1\mathrm{.}33e^{-4t}]u(t)$