# If $\begin{bmatrix} 1 & -1 & x \\ 1 & x & 1 \\ x & -1 &1 \end {bmatrix}$ has no inverse, then the real value of x is :
$\begin {array} {1 1} (1)\;2 & \quad (2)\;3 \\ (3)\;0 & \quad (4)\;1 \end {array}$