27a+6b+c = 0
a+b+c+d = 2/3
6a+2b=0
3a+2b+c = -2 | * 2
6a +2b =0
6a +4b+2c = -4 | abziiehen
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-2 b - 2c = 4
-b - c = 2
27a+6b + c = 0
3a + 2b + c = -2 | * 9
27a+6b + c = 0
27a + 18b + 9c = -18 | abziehen
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- 12 b - 8c = 18
-b - c = 2
c = - 2 - b
- 12 b - 8c = 18
- 12b - 8 * ( -2 -b ) = 18
-12b + 16 + 8b = 18
-4b = 2
b = - 1/2
Kannst du den Rest allein ?
f(x) = 1/6·x^3 - 1/2·x^2 - 3/2·x + 5/2