y = x² + 9x + 8
delta = Δ = b² - 4ac = 9² - 4 · 1 · 8 = 81 - 32 = 49
Miejsca zerowe:
[tex]x_{1} =\frac{-b-\sqrt{delta} }{2a}=\frac{-9-\sqrt{49} }{2*1} =\frac{-9-7}{2} =\frac{-16}{2} =-8[/tex]
[tex]x_{2} =\frac{-b+\sqrt{delta} }{2a}=\frac{-9+\sqrt{49} }{2*1} =\frac{-9+7}{2} =\frac{-2}{2} =-1[/tex]
Postać iloczynowa: f(x) = (x+8)(x+1)
