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Find the values of k for roots are real and equal in equation:(k + 1)x2 + 2(k + 3)x + (k + 8) = 0 |
Answer» The given equation (k +1)x2 + 2(k +3)x + (k +8) = 0 is in the form of ax2 + bx + c = 0 Where a = (k +1), b = 2(k + 3), c = (k + 8) For the equation to have real and equal roots, the condition is D = b2 – 4ac = 0 ⇒ (2(k + 3))2 – 4(k +1)(k + 8) = 0 ⇒ 4(k +3)2 – 4(k2 + 9k + 8) = 0 ⇒ (k + 3)2 – (k2 + 9k + 8) = 0 ⇒ k2 +6k + 9 – k2 – 9k – 8 = 0 ⇒ -3k + 1 = 0 ⇒ k = \(\frac{1}{3}\) So, the value of k is \(\frac{1}{3}\). |
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