New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    What are the values of k, if the roots of the equation

    x² + 2(k - 4)x + 2k = 0 are equal?
    A 3, 2 Correct Answer Incorrect Answer
    B 5, 2 Correct Answer Incorrect Answer
    C 6, 3 Correct Answer Incorrect Answer
    D 8, 2 Correct Answer Incorrect Answer

    Solution

    Given, the roots of the equation x² + 2(k - 4)x + 2k = 0 are equal. When roots are equal then b² = 4ac ⇒ [2(k - 4)]² = 4 * 1 * 2k ⇒ 4(k - 4)² = 8k ⇒ k² - 8k + 16 = 2k ⇒ k² - 10k + 16 = 0 ⇒ (k - 2) (k - 8) = 0 ⇒ k = 2, 8

    Practice Next

    Relevant for Exams: