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Question
If the equation 9x2 + 6kx + 4 = 0 has equal roots then k = ?
Options
2 or 0
–2 or 0
2 or –2
0 only
MCQ
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Solution
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
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