Question

I mean synthetic division I mean.
Thank you so much!

Answer 1

Factorize by grouping :)
First and second term a group, third and fourth term a group.

Answer 2

\[\large x^3+2x^2+4x+8=x^2(x+2)+4(x+2)=(x^2+4)(x+2)\]
\[\large=(x+2i)(x-2i)(x+2)\]

Answer 3

kenny you're smart.