Ответ:

x^3 + x^2 — 4x — 4 = 0

x^2 (x + 1 ) — 4 (x +1) = 0        

(x+1) (x^2 — 4) = 0

x+2 = 0   i   x^2 — 4 = 0

x = — 2     i    (x+2)(x-2) = 0

                     x + 2 = 0   i  x — 2 = 0

                     x= — 2           x = 2