Answer
~$\begin{bmatrix}
2 & 4 & 6\\
5 & 1 & 7\\
6 & 3 & 10
\end{bmatrix}
$
Work Step by Step
~$\begin{bmatrix}
2 & 4 & 6\\
5 & 1 & 7\\
6 & 3 & 10
\end{bmatrix}
$ Divide elements of row 1 by 2
~$\begin{bmatrix}
1 & 2 & 3\\
5 & 1 & 7\\
6 & 3 & 10
\end{bmatrix}
$ Add row 2 to row 1
~$\begin{bmatrix}
6 & 3 & 10\\
5 & 1 & 7\\
6 & 3 & 10
\end{bmatrix}
$ Subtract row 1 from row 3
~$\begin{bmatrix}
6 & 3 & 10\\
5 & 1 & 7\\
0 & 0 & 0
\end{bmatrix}
$ Multiply elements of row 2 by 6/5
~$\begin{bmatrix}
6 & 3 & 10\\
6 & 6/5 & 42/5\\
0 & 0 & 0
\end{bmatrix}
$ Multiply elements of row 2 by 6/5
~$\begin{bmatrix}
6 & 3 & 10\\
6 & 6/5 & 42/5\\
0 & 0 & 0
\end{bmatrix}
$ Subtract row 1 from row 2
~$\begin{bmatrix}
6 & 3 & 10\\
0 & 9/5 & 8/5\\
0 & 0 & 0
\end{bmatrix}
$ Subtract row 1 from row 2
Because all elements of the last row is 0, it columns don't span $R^3$