$$c.s=\left\{\frac{\left(-3+\sqrt[]{41}\right)}{4};\frac{\left(-3-\sqrt[]{41}\right)}{4}\right\}$$  

$$c.s=\left\{\frac{\left(-7+\sqrt[]{31}\right)}{2};\frac{\left(-8-\sqrt[]{57}\right)}{2}\right\}$$  

$$c.s=\left\{-5;5\right\}$$  

$$c.s=\left\{\frac{\left(-5+\sqrt[]{42}\right)}{4};\frac{\left(-5-\sqrt[]{42}\right)}{4}\right\}$$