x2 + x + 1 = 0

(iii) x² + x + 1 = 0

Sol. x² + x + 1 = 0

Comparing with ax² + bx + c = 0 we have a = 1, b = 1, c = 1

∆  = b² – 4ac

= (1)² – 4 (1) (1)

= 1 – 4

= – 3

∴ ∆  = – 3