Find the value(s) of k for which the quadratic equation

x 2 + 2√2 kx + 18 = 0 has equal roots

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  1. Class 10
  2. Solutions of Sample Papers for Class 10 Boards

Transcript

Question 20 Find the value(s) of k for which the quadratic equation x2 + 2√2 π‘˜π‘₯ + 18 = 0 has equal roots x2 + 2√2 π‘˜π‘₯ + 18 = 0 Comparing equation with ax2 + bx + c = 0 a = 1, b = 2√2k , c = 18 Since the equation has 2 equal roots, D = 0 b2 – 4ac = 0 Putting values (2√2k)2 – 4 Γ— 1 Γ— 18 = 0 22 Γ— (√2)^2Γ— k2 – 72 = 0 4 Γ— 2 Γ— k2 = 72 8k2 = 72 k2 = 72/8 k2 = 9 k = Β± √9 k = Β± 3

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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.