$$\left. \begin{array} { l } { B = B U A ( b ) B = B A , } \\ { A = \{ 1 , 2 , 3 , 10 \} } \\ { A = \{ 1 , \right.$$
$B=0\text{, }U\in \mathrm{R}\text{, }A\in \mathrm{R}\text{, }b\in \mathrm{R}$
$B=\frac{1}{AUb}\text{, }U\neq 0\text{, }A\neq 0\text{, }b\neq 0$
