x^4+x^2+1=(x^4+2x^2+1)-x^2=(x²+1)²-x²=[(x²+1)+x][(x²+1-x)]=(x²+x+1)(x²-x+1)
x^4+x^2+1=（x^4+2x^2+1）-x^2=(x^2+1)^2-x^2=(x^2+x+1)(x^2-x+1)
