Respuesta :

ghanami
hello: 
an equation is : f(x) = a(x-0)² +0
the point (2 , -2)in parabola : -2= a(2-0)² +0 
-2=4a
a =-1/2  is the coefficient of the squared expression in the parabola equation
the vertex form is m f(x) = -1/2x²