$x^2+4x-45$ = 0

D = $2^2-\left(-45\right)$ = $4$$+$ $45$ = $49$

x_1,2 = $-2$ ± $\sqrt{49}$

x₁ = $-2$ - $7$ = -9

x₂ = $-2$ + $7$ = 5

L = { $-9$; $5$}

$3x-18+x^2$ = 0

sortieren

$x^2+3x-18$ = 0

D = ${\left(\frac{3}{2}\right)}^2-\left(-18\right)$ = $\frac{9}{4}$$+$ $18$ = $\frac{9}{4}$$+$ $\frac{72}{4}$ = $\frac{81}{4}$

x_1,2 = $-\frac{3}{2}$ ± $\sqrt{\frac{81}{4}}$

x₁ = $-\frac{3}{2}$ - $\frac{9}{2}$ = $-\frac{12}{2}$ = -6

x₂ = $-\frac{3}{2}$ + $\frac{9}{2}$ = $\frac{6}{2}$ = 3

L = { $-6$; $3$}