y2 – 4y – 1 = 0

(i) y² – 4y – 1 = 0

Sol. y² – 4y – 1 = 0

Comparing with ay² + by + c = 0 we have a = 1, b = – 4, c = – 1

∆  = b² – 4ac

= (– 4)² – 4 (1) (-1)

= 16 + 4

= 20

∴ ∆  > 0

Hence roots of the quadratic equation are real and unequal.