6(X^4+1)+5X(X^2+1)-38X^2
=6[(X^2+1)^2-2X^2]+5X(X^2+1)-38X^2
=6(X^2+1)^2+5X(X^2+1)-50X^2
.
=(X-2)(X+3)(3x+1)(2x-1)
6X^4+5X^3-38X^2+5X+6
=(6x^4-15x^3+6x^2)+(20x^3-50x^2+20x)+(6x^2-15x+6)
=3x^2(2x^2-5x+2)+10x(2x^2-5x+2)+3(2x^2-5x+2)
=(3x^2+10x+3)(2x^2-5x+2)
=(3x+1)(x+3)(2x-1)(x-2)
你演算一下,哪个对.