# If one of the roots of $\begin {vmatrix} 3 & 5 & x \\ 7 & x & 7 \\ x & 5 & 3 \end {vmatrix}=0$ is $-10,$ then the other roots are :

$\begin {array} {1 1} (1)\;3,7 & \quad (2)\;4,7 \\ (3)\;3,9 & \quad (4)\;3,4 \end {array}$

(1) 3,7