Respuesta :

choixongdong
x = –4c
if c = -2 then x = -4(-2) = 8

I believed you  had a typo, function should be f(x) = -3x^2 - 4x 
so
f(x) = -3x^2 - 4x 
f(x) = -3(8^2) - 4(8)
f(x) = -3(64) - 32
f(x) = -192 - 32
f(x) = -224

answer

C.
–224