Gruppe A

$a{x}^2+bx+c=0$

$x_{\mathrm{1,2}}={\displaystyle \frac{-b\pm \sqrt{b^2-4ac}}{2a}}$

$2x^2+x-10=0$

$\Rightarrow$ $a=2$; $b=1$; $c=-10$

$x_{\mathrm{1,2}}={\displaystyle \frac{-1\pm \sqrt{(1{)}^2-4\cdot 2\cdot (-10)}}{2\cdot 2}}$

$x_{\mathrm{1,2}}={\displaystyle \frac{-1\pm \sqrt{1+80}}{4}}$

$x_{\mathrm{1,2}}={\displaystyle \frac{-1\pm 9}{4}}$

$x_1=2$; $x_2=-\mathrm{2,5}$