x2 + 4x + k = 0

(vi) x² + 4x + k = 0

Sol. x² + 4x + k = 0

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

∆  = b² – 4ac

= (4)² – 4 (1) (k)

= 16 – 4k

∴ ∆  = 16 – 4k