For what values of k, the equation 9x 2 + 6kx + 4 = 0 has equal roots?

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Question 6 For what values of k, the equation 9x2 + 6kx + 4 = 0 has equal roots?Given equation 9x2 + 6kx + 4 = 0 Since it has equal roots D = 0 b2 − 4ac = 0 Putting a = 9, b = 6k, c = 4 (6k)2 − 4(9)(4) = 0 36k2 = 4 × 9 × 4 k2 = (4 × 9 × 4)/36 k2 = 4 k = ± 2 Thus, k = 2, −2

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.