Given $ A = \begin{bmatrix} 1 & 0 & 0 \\ 0 & -1 & 0 \\ 0 & 0 & -1 \end{bmatrix} $ and $ B = \begin{bmatrix} 2 & x & x \\ x & 4 & 5 \\ x & 6 & 7 \end{bmatrix} $. Then find the value of `x` (if possible) such that `AB = BA`