x^2+x+1=0
x^4+2x^3+4x^2+3x+2
=(x^4+x^3+x^2)+(x^3+x^2+x)+(2x^2+2x+2)
=x^2(x^2+x+1)+x(x^2+x+1)+2(x^2+x+1)
=(x^2+x+1)(x^2+x+2)
=0
x^2+x+1=0
x^4+2x^3+4x^2+3x+2
=(x^4+x^3+x^2)+(x^3+x^2+x)+(2x^2+2x+2)
=x^2(x^2+x+1)+x(x^2+x+1)+2(x^2+x+1)
=(x^2+x+1)(x^2+x+2)
=0