carilah rumus f(x) dari ax^+bx+c jika f(0) =-5,f(-1)=1 dan f(2)=9

f(x)= ax²+bx+c
f(0)= 5
f(-1)= 1
f(0)= a(0²)+b(0)+c=5
c=5
f(-1)= a-b+5=1
a-b= -4....(4)
f(2)= 4a+2b+5=9
4a+2b= 4....(5)
(4)x2=2a-2b= -8...(6)
(5)+(6)=6a=-4
a= -2/3
substitusi a=-2/3 ke (6)
2.-2/3 - 2b= -8
-4/3 - 2b= -8
b= 10/3
f(x)= -2/3x²+10/3x+5