Chapter 9.7, Problem 15E

In Problems 11-16, use the variation of parameters formula (11) to find a general solution of the system $x^{\prime }\left(t\right)=Ax\left(t\right)+f\left(t\right)$, where A and $f\left(t\right)$ are given.

$A=\left[\begin{array}{cc}-4& 2\\ 2& -1\end{array}\right],f\left(t\right)=\left[\begin{array}{c}{t}^{-1}\\ 4+2t^{-1}\end{array}\right]$