\usepackage{amsmath}

\[
\rightsquigarrow
\begin{array}{r}
R_1\\
R_2-3R_1\\
R_3-2R_1\\
R_4+R_1
\end{array}
\begin{pmatrix}
1& 3& -4& 3\\
0& -4& 14& -7 \\
0& -8& 13& -7 \\
0 & 6& -3& 0
\end{pmatrix}
\rightsquigarrow \qquad 
\begin{array}{r}
R_1\\
R_2\\
R_3\\
R_4+R_2
\end{array}
\begin{pmatrix}
1& 3& -4& 3\\
0& -4& 14& -7 \\
0& -8& 13& -7 \\
0 & 2& 11& -7
\end{pmatrix}
\]