x2 + 4x + 1 = 0

(i) x² + 4x + 1 = 0

Sol. x² + 4x + 1 = 0

Comparing with ax² + bx + c = 0 we have a = 1, b = 4, c = 1

∆  = b² – 4ac

= (4)² – 4 (1) (1)

= 16 – 4

= 12

∴ ∆  = 12