$x^2-14x+45$ = 0

D = ${\left(-7\right)}^2-45$ = $49$ $-$ $45$ = $4$

x_1,2 = $7$ ± $\sqrt{4}$

x₁ = $7$ - $2$ = 5

x₂ = $7$ + $2$ = 9

L = { $5$; $9$}

$-8+7x+x^2$ = 0

sortieren

$x^2+7x-8$ = 0

D = ${\left(\frac{7}{2}\right)}^2-\left(-8\right)$ = $\frac{49}{4}$$+$ $8$ = $\frac{49}{4}$$+$ $\frac{32}{4}$ = $\frac{81}{4}$

x_1,2 = $-\frac{7}{2}$ ± $\sqrt{\frac{81}{4}}$

x₁ = $-\frac{7}{2}$ - $\frac{9}{2}$ = $-\frac{16}{2}$ = -8

x₂ = $-\frac{7}{2}$ + $\frac{9}{2}$ = $\frac{2}{2}$ = 1

L = { $-8$; $1$}