Solve the equation $$2 x + 3 y + 9 z = -11.$$
$\displaystyle \left\lbrack \begin{array}{c} x \\ y \\ z \end{array} \right\rbrack =$ $\left[\Rule{0pt}{3.6em}{0pt}\right.$$\left]\Rule{0pt}{3.6em}{0pt}\right.$ $+ s$ $\left[\Rule{0pt}{3.6em}{0pt}\right.$$\left]\Rule{0pt}{3.6em}{0pt}\right.$ $+ t$ $\left[\Rule{0pt}{3.6em}{0pt}\right.$$\left]\Rule{0pt}{3.6em}{0pt}\right.$