Question 636099
<img src="http://latex.codecogs.com/gif.latex?\begin{array}{rl} x-7y+z &= 15 \\y+6z &= 14 \\z &= 11 \\ \end{array}" title="x" />


is the same as


<img src="http://latex.codecogs.com/gif.latex?\begin{array}{rl} x-7y+z &= 15 \\0x+y+6z &= 14 \\0x+0y+z &= 11 \\ \end{array}" title="x" />


which translates to the following matrix


<img src="http://latex.codecogs.com/gif.latex?\left[ \begin{array}{ccc|c} 1 & -7 & 1 & 15 \\0 & 1 & 6 & 14 \\0 & 0 & 1 & 11 \\ \end{array}\right]" />