1.△=b^2-4ac=k^2+4>0,所以有两个不相等的实数根2.由韦达定理知,x1+x2=-b/a=-k,x1*x2=c/a=-1,1/x1=2-1/x21/x1+1/x2=2又,(x1+x2)/2=x1*x2,所以-k/2=-1,k=2x1+x2=-1,x1-x2=1x1=0,x2=-1把x=0代入,c-a=0,c=a把x=-1代入,2...