\(\left(x+1\right)^4+\left(x^2+x+1\right)^2\)
\(=\left(x^2+2x+1\right)^2+\left(x^2+x+1\right)\)
\(=x^4+4x^3+6x^2+4x+1+x^4+2x^3+3x^2+2x+1\)
\(=2x^4+6x^3+9x^2+6x+2\)
\(=2x^4+2x^3+x^2+4x^3+4x^2+2x+4x^2+4x+2\)
\(=x^2\left(2x^2+2x+1\right)+2x\left(2x^2+2x+1\right)+2\left(2x^2+2x+1\right)\)
\(=\left(x^2+2x+2\right)\left(2x^2+2x+1\right)\)