是x³-x²-16x+28=0吗？如果是，那么：解：x³-2x²+x²-2x-14x+28=0x²(x-2)+x(x-2)-14(x-2)=0(x-2)(x²+x-14)=0(x-2)(x²+x+¼ -57/4)=0(x-2)[(x+½)²-57/4]=0(x-2)(x+½+ √57/2)(x+½- √57/2)=0x=2或x=-(1+√57)/2或x=(√57-1)/2
