Answer:
we approach the issue by taking note of that a 2 x 2 matrix can either have 1 0r 2 pivot columns. If the matrix has no pivot columns then every entry in the matrix must be zero.
-> if our matrix has two pivot columns then : [tex]\left(\begin{array}{rr}-&*&0&-\end{array}\right)[/tex]
-> if our matrix has one pivot column then we have a choice to make. If the first column is pivot column then: [tex]\left(\begin{array}{rr}-&*&0&0\end{array}\right)[/tex]
->otherwise, if the pivot column is the second column then: [tex]\left(\begin{array}{rr}0&-&0&0\end{array}\right)[/tex]
