For which values of kkk does x2+kx+9=0x^2 + kx + 9 = 0x2+kx+9=0 have no real solutions?
−6<k<6-6 < k < 6−6<k<6
k>6k > 6k>6 or k<−6k < -6k<−6
k=6k = 6k=6
k=−6k = -6k=−6