For what aaa does x2−ax+1=0x^2 - ax + 1 = 0x2−ax+1=0 have real roots?
a≤−2a \leq -2a≤−2 or a≥2a \geq 2a≥2
−2<a<2-2 < a < 2−2<a<2
a>2a > 2a>2
a<−2a < -2a<−2