$$\left. \begin{array} { l } { x ( b + c ) = ( a + b ) + ( a \times c ) a = \frac { 3 } { 3 } b = \frac { 5 } { 3 } c - \frac { 5 } { 3 } } \\ { \text { 20 ) E x p r e \right.$$
$\left\{\begin{matrix}x=\frac{a+b+ca^{2}}{b+c}\text{, }&b\neq -c\\x\in \mathrm{R}\text{, }&b=-\frac{a}{1-a^{2}}\text{ and }c=\frac{a}{1-a^{2}}\text{ and }|a|\neq 1\end{matrix}\right.$
