Using Variation of Parameters method solve the $2$nd$-$order linear non$-$homogeneous DE$,$

$y^{\text{'}\text{'}}+27y^{\text{'}}+162y=\frac{13}{1+e^{9x}}$

The complimentary solution of the equation is

$y_c(x)=c1e^{-18x}+c2e^{-9x}$

where $c_1$ and $c_2$ are arbitrary constants.

A particular solution of the equation is

$y_p(x)=$

$$

The general solution of the non$-$homogeneus equation is

$y(x)=$

$$

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