[tex]2 n^{2} - 4n + 10 n - 20 = 0
[/tex]
[tex]2 n^{2} + 6n - 20 =0[/tex] / : 2
[tex]n^{2} + 3n - 10 =0[/tex]
Δ= [tex] b^{2} - 4ac[/tex]
Δ= 9+40
Δ= 49
n₁,₂= [tex] \frac{-b +- \sqrt{Δ} }{2a} [/tex]
n₁,₂= [tex] \frac{-1 +- \sqrt{49} }{2} [/tex]
n₁,₂= [tex] \frac{-1 +- 7}{2} [/tex] =>
=> n₁= [tex] \frac{6}{2} [/tex] = 3
=> n₂=[tex] \frac{-8}{2} [/tex] = -4
S={-4, 3}
