原式=x^4 +2x^2+1+ 7x^3 +7x -2x^2+14x^2
=(x^2+1)^2+7x(x^2+1)+12x^2
=(x^2+1+3x)(x^2+1+4x)
=(x^2 +3x+1)(x^2+4x+1)