Question

If the equation 9x² + 6kx + 4 = 0 has equal roots then k = ?

पर्याय

• 2 or 0

• –2 or 0

• 2 or –2 

• 0 only

Answer 1

2 or –2 

Explanation:

It is given that the roots of the equation (9x² + 6kx + 4 = 0) are equal.

∴ (b² – 4ac) = 0

⇒ (6k)² – 4 × 9 × 4 = 0

⇒ 36k² = 144

⇒ k² = 4

⇒ k = ±2