k^3+k^2-7k-3=k^3+k^2-6k-k-3=k(k^2+k-6)-(k+3)=k(k+3)(k-2)-(k+3)=(k+3)(k^2-2k-1)=0k=-3或k^2-2k-1=0即k=-3或k=1+根号2或1-根号2
