Chapter 4.7, Problem 4P

In each of Problems 2 through 5, use the method of variation of parameters to find a particular solution using the given fundamental set of solutions $\left\{x_1,x_2\right\}$.

$x\text{'}=\left(\begin{array}{cc}-1& 0\\ -1& -1\end{array}\right)x+\left(\begin{array}{l}-6\\ 9t\end{array}\right)$,

$x_1=e^{-t}\left(\begin{array}{l}0\\ 1\end{array}\right)$,        $x_2=e^{-t}\left(\begin{array}{c}-1\\ t\end{array}\right)$