With the given matrix, the system of equations you have is:
[tex]\begin{gathered} x_1+2x_2-x_4-3x_5=2 \\ x_3+3x_4-3x_5=1 \\ x_4-\frac{1}{6}x_5=\frac{1}{2} \\ x_5=\frac{3}{11} \end{gathered}[/tex]Then, you already know x5=3/11.
Now replace these value in the equation above and solve for x4:
[tex]\begin{gathered} x_4-\frac{1}{6}\cdot\frac{3}{11}=\frac{1}{2}^{} \\ x_4-\frac{3}{66}=\frac{1}{2} \\ x_4-\frac{1}{22}=\frac{1}{2} \\ x_4=\frac{1}{2}+\frac{1}{22} \\ x_4=\frac{22+2}{44}=\frac{24}{44} \\ x_4=\frac{6}{11} \end{gathered}[/tex]Now, replace x4 and x5 into the next above equation:
[tex]\begin{gathered} x_3+3\cdot\frac{6}{11}-3\cdot\frac{3}{11}=1 \\ x_3+\frac{18}{11}-\frac{9}{11}=1 \\ x_3+\frac{9}{11}=1 \\ x_3=1-\frac{9}{11}=\frac{11-9}{11} \\ x_3=\frac{2}{11} \end{gathered}[/tex]