Question

The equation 12x² + 4kx + 3 = 0 has real and equal roots, if:

Options

• k = ±3

• k = ±9

• k = 4

• k = ±2

Answer 1

k = ±3

Explanation:

Here a = 12, b = 4k, c = 3

Since the given equation has real and equal roots

∴ b² – 4ac = 0

⇒ (4k)² – 4 × 12 × 3 = 0

⇒ 16k² – 144 = 0

⇒ k² = 9

⇒ k = ±3