$$\left. \begin{array} { l } { \frac { 12 c c - 3 c - 1 } { 20 } = \frac { 12 c - 6 } { 12 c - 3 c - 10 } = \frac { 180 } { 20 - 60 } = } \\ { \text { p o i n a l e s f o r t h e f o r e s e n c h c h e \right.$$
$c=\frac{-22\sqrt{85}\cos(\frac{\arccos(\frac{61037\sqrt{85}}{9616475})}{3})+49}{108}\approx -1.190756048$
$c=\frac{11\sqrt{85}\cos(\frac{\arccos(\frac{61037\sqrt{85}}{9616475})}{3})+11\sqrt{255}\sin(\frac{\arccos(\frac{61037\sqrt{85}}{9616475})}{3})+49}{108}\approx 2.061511726$
$c=\frac{11\sqrt{85}\cos(\frac{\arccos(\frac{61037\sqrt{85}}{9616475})}{3})-11\sqrt{255}\sin(\frac{\arccos(\frac{61037\sqrt{85}}{9616475})}{3})+49}{108}\approx 0.490355433$
