$x^2+8x+15$ = 0

D = $4^2-15$ = $16$ $-$ $15$ = $1$

x_1,2 = $-4$ ± $\sqrt{1}$

x₁ = $-4$ - $1$ = -5

x₂ = $-4$ + $1$ = -3

L = { $-5$; $-3$}

$x^2+70+17x$ = 0

sortieren

$x^2+17x+70$ = 0

D = ${\left(\frac{17}{2}\right)}^2-70$ = $\frac{289}{4}$ $-$ $70$ = $\frac{289}{4}$$-$ $\frac{280}{4}$ = $\frac{9}{4}$

x_1,2 = $-\frac{17}{2}$ ± $\sqrt{\frac{9}{4}}$

x₁ = $-\frac{17}{2}$ - $\frac{3}{2}$ = $-\frac{20}{2}$ = -10

x₂ = $-\frac{17}{2}$ + $\frac{3}{2}$ = $-\frac{14}{2}$ = -7

L = { $-10$; $-7$}