$$\left. \begin{array} { l } { A = [ \frac { - 1 } { 4 } , \frac { 1 } { 4 } , 8 = [ 3 , 4 ] } \\ { A = [ 2 , 4 ] ^ { 8 } } \end{array} \right.$$
$A=-\frac{1}{4},\ \text{false},\ A=2,\ a=\frac{1}{4},\ b=4,\ c=4$
