ix2 – 4x – 4i = 0
Multiplying throughout by i, we get
i2x2 – 4ix – 4i2 = 0
-x2 – 4ix + 4 = 0 …[∵ i2 = -1]
x2 + 4ix – 4 = 0
Comparing with ax2 + bx + c = 0, we get
a = 1, b = 4i, c = -4
Discriminant = b2 – 4ac
= (4i)2 – 4 × 1 × (-4)
= 16i + 16
= -16 + 16
= 0
So, the given equation has equal roots.
These roots are given by
∴ The root of the given equation is -2i.