Find the System of Linear Equations Represented by the Augmented $\left[ \begin{array} { c c c c } 1&-1&6 &\vdots& 8 \\0&1&-1 &\vdots& 6 \\0 & 0 & 1 &\vdots&-6\\\end{array} \right]$

Multiple Choice

Find the system of linear equations represented by the augmented matrix.Then use back substitution to solve.(Use variables x, y, z and if applicable.) $\left[ \begin{array} { c c c c } 1&-1&6 &\vdots& 8 \\0&1&-1 &\vdots& 6 \\0 & 0 & 1 &\vdots&-6\\\end{array} \right]$

A) $\left\{ \begin{aligned}x - y + 6 z & = 8 \\y + z & = 6 \\z & = - 6\end{aligned} \right.$ (56, 12, -6)
B) $\left\{ \begin{aligned}x - y + 6 z & = 8 \\y - z & = - 6 \\z & = 6\end{aligned} \right.$ (44, 0, -6)
C) $\left\{ \begin{array} { r } x - y + 6 z = 8 \\y + z = 6 \\z = 6\end{array} \right.$ (-40, 12, 6)
D) $\left\{ \begin{aligned}x - y + 6 z & = 8 \\y - z & = 6 \\z & = - 6\end{aligned} \right.$ (44, 0, -6)
E) $\left\{ \begin{aligned}x - y + 6 z & = 8 \\y + z & = - 6 \\z & = 6\end{aligned} \right.$ (-40, 12, 6)