\(x^4+x+2x^2+x+1\)
\(=\left(x^4+2x^2+1\right)+\left(x^3+x\right)\)
\(=\left(x^2+1\right)^2+x\left(x^2+1\right)\)
\(=\left(x^2+1\right)\left(x^2+1+x\right)\)
\(x^4+x^3+2x^2+x+1\)
=\(x^2\left(x^2+x+1\right)+\left(x^2+x+1\right)\)
=\(\left(x^2+x+1\right)\left(x^2+1\right)\)