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