Помогите решить методом гауса

Решите задачу:

$\left[\begin{array}{ccc|c|c}3&-5&1&-11&\downarrow\\-4&1&-7&9&\\1&6&-3&4&\uparrow\end{array}\right]\ \textgreater \ \left[\begin{array}{ccc|c|c}1&6&-3&4&\downarrow\\-4&1&-7&9&4\\3&-5&1&-11&-3\end{array}\right]\ \textgreater \ \\\ \textgreater \ \left[\begin{array}{ccc|c|c}1&6&-3&4&\\0&25&-19&25&:25\\0&-23&10&-23&\end{array}\right]\ \textgreater \ \left[\begin{array}{ccc|c|c}1&6&-3&4&-6\\0&1&-\frac{19}{25}&1&\updownarrow\\0&-23&10&-23&23\end{array}\right]$
$\left[\begin{array}{ccc|c|c}1&0&\frac{39}{25}&-2&\\0&1&-\frac{19}{25}&1&\\0&0&-\frac{187}{25}&0&*-\frac{25}{187}\end{array}\right]\ \textgreater \ \left[\begin{array}{ccc|c|c}1&0&\frac{39}{25}&-2&-\frac{39}{25}\\0&1&-\frac{19}{25}&1&\frac{19}{25}\\0&0&1&0&\uparrow\end{array}\right]\ \textgreater \ \\\ \textgreater \ \left[\begin{array}{ccc|c|c}1&0&0&-2&\\0&1&0&1&\\0&0&1&0&\end{array}\right]$