For which kkk does x2+kx+1=0x^2 + kx + 1 = 0x2+kx+1=0 have real roots?
∣k∣≥2|k| \geq 2∣k∣≥2
∣k∣≤2|k| \leq 2∣k∣≤2
k>2k > 2k>2
k<−2k < -2k<−2