Respuesta :

hello :
f(x) = a(x-1)(x-0)
f(x) = ax(x-1)
find : a 
(1/2, -2/3) lie in parabola : -2/3 = a(1/2) (1/2-1)
 (1/4)a = 2/3
a = (4)(2)/3 = 8/3
f(x) = (8/3)x(x-1)