, 6. Let \[A(x)=\left(\begin{array}{cc} 2 & 1+2 x \\ 1 & 2 \end{array} ight) \in M(2, \mathbb{R}),\quad x \in \mathbb{R}. \] Consider the open ball \[B_{1}(A(1)):=\{C \in M(2, \mathbb{R}) \mid\|C-A(1)\|