Answer
$\left[\begin{array}{lllll}
1 & 2 & 2 & | & 2\\
0 & 1 & -1 & | & 2\\
0 & 0 & 9 & | & -9
\end{array}\right]$
Work Step by Step
The elements of the third row will be replaced with
$0\rightarrow\quad-5(0)+0=0$
$5\rightarrow\quad-5(1)+5=0 $
$4\rightarrow\quad-5(-1)+4=9 $
$1\rightarrow\quad-5(2)+1=-9$
so the new matrix is
$\left[\begin{array}{lllll}
1 & 2 & 2 & | & 2\\
0 & 1 & -1 & | & 2\\
0 & 0 & 9 & | & -9
\end{array}\right]$
