Question 430059
{{{f(x)=-(2/3)(x^2+2*4*x+4^2)+4/3}}}=
{{{-(2/3)x^2-(16/3)x-32/3+4/3}}}=
{{{(-2/3)x^2+(-16/3)x-28/3}}}=
{{{(-2/3)x^2+(-16/3)x-28/3}}}
a=-2/3 b=-16/3 c=-28/3