Each augmented matrix is in row-echelon form. Assume that the variables are $x, y,$ and $z$ and use back-substitution to obtain the solution of the associated system of linear equations.
$$
\left[\begin{array}{lll|l}
1 & 1 & 4 & 6 \\
0 & 1 & 2 & 4 \\
0 & 0 & 1 & \frac{1}{2}
\end{array}\right]
$$