a,
\(3(x^{4}+x^{2}+1)-(x^{2}+x+1)^{2}\\=3[(x^{4}+2x^{2}+1)-x^{2}]-(x^{2}+x+1)^{2}\\=3[(x^{2}+1)^{2}-x^{2}]-(x^{2}+x+1)^{2}\\=3(x^{2}+x+1)(x^{2}-x+1)-(x^{2}+x+1)^{2}\\=(x^{2}+x+1)(3x^{2}-3x+3-x^{2}-x-1)\\=(x^{2}+x+1)(2x^{2}-4x+2)\\=2(x^{2}+x+1)(x^{2}-2x+1)\\=2(x^{2}+x+1)(x-1)^{2}\)