<<VilGebra`

Determinante[(({{1, 0, -3, 0}, {2, k, -1, 1}, {1, 2, k, 0}, {k, 1, 0, -1}}))]
Determinante[(({{k, -1, 1}, {2, k, 0}, {1, 0, -1}})),fila->2]
Determinante[(({{2, k, 1}, {1, 2, 0}, {k, 1, -1}})),fila->2]
Solve[Det[(({{1, 0, -3, 0}, {2, k, -1, 1}, {1, 2, k, 0}, {k, 1, 0, -1}}))]==0,k]