Question

$x^{3}+ 4x^{2}-4x-16=0$

Answer 1

x³+4x²-4x-16=0
x²(x+4)-4(x+4)=0
(x+4)(x²-4)=0
x+4)(x+2)(x-2)=0
x₁=-4  x₂=2  x₃=-2.

Answer 2

$x^3+4x^2-4x-16=0\\ x^3-4x+4x^2-16=0\\ x(x^2-4)+4(x^2-4)=0\\ (x+4)(x^2-4)=0$

$\left\|{{x+4=0} \atop{x^2-4=0} } \left\|{ {{x=-4} \atop {x^2=4}} \left\|{ {{x=2} \atop {x=-2}} \right.$
Ответ: $-4;2;-2$