韦达定理x1+x2=-(2k+1)x1x2=k²-2x1²+x2²=11所以(x1+x2)²-2x1x2=114k²+4k+1-2k²+4=11k²+2k-3=0(k+3)(k-1)=0k=-3,k=1判别式大于等于0(2k+1)²-4(k²-2)>=0k=1都符合所以k=1韦达定理x1+x2=-3x1x2=-1(X1-X2)^2=x1+x2-2x1x2=-1
