首先x^4+6x^2+25=x^4+10x^2+25-4x^2=(x^2+5)^2-4x^2=(x^2+2x+5)(x^2-2x+5)
其次3x^4+4x^2+28x+5=（9x^4+12x^2+84x+15)/3=[(9x^4+48x^2+64)-(36x^2-84x+49)]/3=[(3x^2+8)^2-(6x-7)^2]/3=(3x^2+8+6x-7)(3x^2+8-6x+7)/3=(3x^2+6x+1)(3x^2-6x+15)/3=(3x^2+6x+1)(x^2-2x+5)
你好！
设
3x^4+4x²+28x+5,
= (x^2+ax+b)(3x^2+cx+d)
可以算出结果为
(x^2-2x+5)*(3x^2+6x+1)
