$$S= \{ (3,-2),(4,5) \} para { R }^{ 2 }$$
$R\in \mathrm{C}$
$\left(p=0\text{ or }r=0\text{ or }a=0\right)\text{ and }S=0$
$R\in \mathrm{R}$
$\left(p=0\text{ or }r=0\text{ or }a=0\right)\text{ and }S=0$
