transforming equation systems into matrix form is fairly simple:
each column represents a variable, and each line represents an equation.
So in the first column, the NUMBERS MULTIPLYING by the X variables are put, in the second one the ones multiplying by Y, etc. The constants go after the vertical line, the last column
so we have:
[tex] \left \{ {{x+y=5} \atop {3x-y=-1}} =\{ {{1x+1y=5} \atop {3x+(-1)y=-1}}\right[/tex]
So in a matrix, it will be the one on the picture
