### Perform the indicated operation(s) on the matrix.

\(\left[\begin{array}{rrr|r}-4 & 5 & -2 & 39 \\
-1 & 4 & 0 & 21 \\
-2 & 5 & 4 & 7\end{array}\right]\begin{array}{ll}\phantom{1} & -\frac{1}{4}R_1 \to R_1 \\
\phantom{1} & \\
\phantom{1} & \end{array}\)