$$\left. \begin{array} { l } { 20 = - \infty } \\ { = ( a - 2 a ) - ( - 8 b ) ( - 5 a + 12 a + 10 b ) } \\ { = ( a - 2 a ) - 2 ( a + 2 ) - ( 3 a + 5 ) ( 5 a + 5 ) ( - 2 a + 20 + 5 ) = } \end{array} \right.$$
[No Solution]
