A(2/-16)
B(-4/-40)
C(0/8)
f ( x ) = a*x^2 + b * x + c
f ( 2 ) = a* *2^2 + b * 2 + c = -16
f ( -4 ) = a *(-4)^2 + b * (-4) + c = -40
f ( 0 ) = a * 0^2 + b * 0 + c = 8
4a + 2b + c = -16
16a - 4b + c = -40
c = 8
c Einsetzen
4a + 2b + 8 = -16
16a - 4b + 8 = -40
4a + 2b = -24 | * 2
16a - 4b = -48
8a + 4b = -48
16a - 4b = -48 | addieren
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24a = -96
a = -4
Einsetzen
8*(-4) + 4b = -48
-32 + 4b = -48
4b = -16
b = -4
c = 8
f ( x ) = (-4)*x^2 - 4 * x + 8