Finding $m$ so that the rank of the matrix is even

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Find $m$ so that the rank of the matrix is ​​even $$ A=\begin{pmatrix} 3& 1& m& 1\\ 1&2 &2&m+1\\3& 1& 1&0\\ 6&6&1&8 \end{pmatrix} . $$

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Hint: The first minor is non-zero, so the rank is at least 2. The next possibility is 4, which is connected with singularity of the matrix $A$. It depends on certain quadratic equation.