It all depends on what you already know: we can say that the characteristic polynomial of has free coefficient equal to zero zero is one of the eigenvalues of is singular.

Or we can say that is singular zero is one of the eigenvalues of is singular.

Or we could even say is singular the rows (columns) of , when seen as vectors in the definition field, are linearly dependent when bringing the matrix to echelon form (and thus at most multiplying the matrix's determinant by a non-zero factor) we get a row of zeros .

Choose yours...

Tonio