Răspuns:
f(x) =-3x²+10x+8
Explicație pas cu pas:
f(5/3)=0
a<0 pt ca avem maxim
-b/2a=2/3
-Δ/4a=49/3
convine forma canonica
f(x) =a (x+b/2a)²-Δ/4a
f(x) =a(x+2/3)² +49/3
f(5/3) =0
a(7/3)²+49/3=0
a*49/9=-49/3
a/9=1/3
a/3=-1
a=-3
a=-3
-b/2a=5/3
-b/-6=5/3
b/6=5/3
b/2=5........b=10
-Δ/4a=49/3
-(b²-4ac)/(-12)=49/3
(b²-4ac)/12=49/3
(b²-4ac)/4=49
b²-4ac=196
100-4(-3)*c=196
12c=96
c=8
f(x) =-3x²+10x+8
a iesit frmos la c, nu mai verific toata povestea...dar -b/2a se vede imediat
