$$\left. \begin{array} { l } { 3 + c = 0 } \\ { - 3 + c = 0 } \\ { - 3 + 5 = 3 } \\ { - B - 0 } \\ { - B - D = 1 } \end{array} \right.$$
$c=-3,\ c=3,\ \text{false},\ -B-D=1,\ a=-B$
