$$\left. \begin{array} { l } { p s + p } \\ { p = 5 s = 20 } \end{array} \right.$$
$s=-\frac{\sqrt{20q+25}}{10}-\frac{1}{2}\text{, }p=5s\text{, }q\geq -\frac{5}{4}$
$s=\frac{\sqrt{20q+25}}{10}-\frac{1}{2}\text{, }p=5s\text{, }q\geq -\frac{5}{4}$
