Question

Exercitiul 15 va rog.

Answer 1

$x^2+x+1\stackrel{not}{=}t\\n=t(t+4)+3=t^2+4t+3=t^2+3t+t+3=t(t+3)+(t+3)=\\=(t+3)(t+1)\\\\n=(x^2+x+1+3)(x^2+x+1+1)=(x^2+x+4)(x^2+x+2)\\\text{Hope you understood.}$