If one root of the determinant $\begin{vmatrix}x&3&7\\2&x&2\\7&6&x\end{vmatrix}=0$ is $-9$ then the other two roots are

Question

$(a)\;2,7\qquad(b)\;2,-7\qquad(c)\;-2,7\qquad(d)\;-2,-7$